Vessels Of Rats Research Articles

Folic acid enhances the cardiovascular protective effect of amlodipine in renal hypertensive rats with elevated homocysteine

ABSTRACT Objectives To investigate the actions of amlodipine-folic acid (amlodipine-FA) preparation on hypertension and cardiovascular in renal hypertensive rats with hyperhomocysteinemia (HHcy), so as to provide experimental basis for clinical research of amlodipine folic acid tablets. Methods Rats model of renal hypertension with HHcy were established. The rats were randomly divided into groups of model, amlodipine, folic acid (FA) and amlodipine-FA of various dosages. Normal rats were used as normal control group. Blood pressure, Hcy as well as plasma NO, ET-1 and hemodynamics were assayed. Histological alterations of heart and abdominal aorta were also examined. Results Compared with the normal group, blood pressure, plasma Hcy, and NO of the rats in model group were significantly increased, while the plasma ET-1 was decreased. Compared with the normal group, the animals in the model group had reduced cardiac function, thickened wall of the aorta and narrowed lumen. In FA group and amlodipine group, the rat plasma NO was increased while ET-1 was decreased, the protective effect of amlodipine-FA group on endothelial cells was further enhanced. In amlodipine group, the rat hemodynamics (LVSP, LVEDP and ±dp/dtmax, et al.) and vascular damage were significantly reduced, while in amlodipine-FA group, the heart function were further improved, and myocardial and vascular hypertrophy were significantly reduced. Conclusions As compared to amlodipine alone, amlodipine -FA can lower both blood pressure and plasma Hcy, significantly enhancing vascular endothelial function to protect the heart and blood vessel in renal hypertensive rats with HHcy.

Step By Step Free Flap Training Based on Inferior Superficial Epigastric Vessels in Rats

Introduction: Skill, knowledge and experience are essential in the field of microsurgery. The repetitive practice of free flaps on reliable models represents a valuable asset for each young surgeon, simulating the challenges of a free flap, before attempting human complex reconstructions. Microsurgery free-flap training is a demanding challenge, with limited options depending on local and regional programs, therefore we comprised a practice system that would add and reinforce microsurgical skills of each aspiring surgeon. Materials and Methods: Wistar rats, weighing 300-400 grams were used, the epigastric flap presenting the advantage of low morbidity with possibility of primary closure, while the donor cervical site represents a recipient area with one of the lowest chances of post-surgical self-mutilation areas in murine models. Results: The aim of this paper is to present a step-wise approach on a reliable training model, using living Wistar rats specimens. Microsurgery and super-microsurgery techniques are trained by harvesting a fascio-cutaneous free flap and transferring it to the cervical area. The aforementioned flap presents a pedicle based on the superficial inferior epigastric vessels at the emergence from the femoral vessels which will be anastomosed to an anterior cervical created defect to the carotid artery end-to-side and to the external jugular vein end-to-end, the epigastric vein presenting a diameter of 0.7-0.8 mm and the epigastric artery a diameter of 0.5-0.6 mm. They can be harvested with patches or stumps of femoral vessels for microsurgical training as an easier entry-level option, or directly for super-microsurgical training. Conclusion: This flap represents a reliable living training model, which can develop microsurgical skills involving raising, transferring and in-setting free flaps, providing ample and valuable knowledge and practice, simulating the challenges of a real-life either microsurgical or super-microsurgical intervention.

Effects of lipopolysaccharide stimulation during pregnancy on kidneys and blood vessels in offspring rats

Objective: To investigate the effect of lipopolysaccharide (LPS) inflammatory stimulation during pregnancy on offspring rats. Methods 20 SD pregnant rats were randomly divided into control and LPS groups, with 10 rats in each group. Rats in LPS group received intraperitoneal injection of LPS 0.79 mg/kg on the Days 8th, 10th, and 12th of gestation, and rats in control group received intraperitoneal injection of the same volume of sterile saline. The blood pressure of offspring rats was measured once every two weeks from 8 weeks of age to 16 weeks of age. Protein expression of NF-κB and NOX2 was detected by immunohistochemistry. ROS and NO levels in vascular tissues were observed by staining with DHE and DAF-2DA cular tissues were observed by staining with DHE and DAF-2DA fluorescent probes, respectively. Results At 8, 10, 12, 14 and 16 weeks of age,the systolic blood pressure of offspring in the LPS group was higher than that of the control group at the same age (P< 0.01).The urine volume and urinary sodium excretion rate of the LPS group were significantly lower than those of the control group (P < 0.05), while the urine creatinine and urine protein were not statistically significant as compared with those of the control group. Compared with the control group, the expression of NF-κB, NOX2, Ang II in thoracic aorta, and ROS in mesenteric artery were higher in LPS group. However, mesenteric artery NO expression was lower (P < 0.01) Conclusion LPS inflammatory stimulation during pregnancy causes kidneys inflammation and increased oxidative stress in blood vessels in offspring rats.

Metachromatic, tryptase- and ghrelin-positive mast cells in the blood vessels of rat’s lung

Mast cells and the mediators they release play a major role in the pathogenesis of lung diseases. They regulate the function of the smooth muscle layer of the pulmonary airways and the same layer of the blood vessels. There are no data about the distribution of metachromatic and tryptase-positive mast cells in the blood vessels’ wall as well as on the content of ghrelin in mast cell granules in rat’s lung. The aim of this research was to present an analysis of the number and localisation of tryptase-positive, ghrelin-positive and metachromatic mast cells in the blood vessels (arteries, capillaries, venules and veins) in rats of different age. Six male Wistar rats were used for each age group - 20 days, 3 months and 1 year. Tissue slices for histochemical examination were taken from the caudal lobe of the left lung and stained with toluidine blue. Immunohistochemical reactions were then performed to indicate the expression of tryptase and ghrelin, allowing comparing the presence of tryptase-, ghrelin-positive and metachromatic mast cells in the wall of the blood vessels of different diameters. The light microscopical study showed that in all types of blood vessels from the three age groups, the number of ghrelin positive cells was the largest, followed by tryptase-positive and metachromatic mast cells. The observed differences in the distribution of these cells are important for maintaining the lung homeostasis and can be used as reference values in experimental studies in order to obtain accurate results.

S-12-2: ENHANCING MAS1:ETBR INTERACTION AS A POTENTIAL VASOPROTECTIVE STRATEGY IN STROKE-PRONE SHR

We previously demonstrated that Ang-(1–7) has anti-inflammatory effects in endothelial cells by inducing interaction between Mas1 and ETBR. Using HTS of &gt; 20,000 druggable compounds, we identified several compounds that enhance Mas1:ETBR interaction as a novel strategy to promote vasoprotection. The objective of this study was to evaluate effects of 2 candidate compounds, termed enhancers 3 and 4 (Enh3 and Enh4), on functional responses in vascular smooth muscle cells (VSMCs) and their therapeutic potential in hypertensive (SHRSP) rats. VSMCs from normotensive (WKY) and SHRSP rats were exposed to Enh3 and Enh4(10–5 M; 5–30 mins). Expression of pro-contractile and mitogenic molecules was assessed by immunoblotting. Ca2+ influx was evaluated using fluorescence microscopy. ROCK2 activity was assessed using a colorimetric immunoassay which detected MYPT1 phosphorylation at Thr696. Male SHRSP rats (18–21weeks) were treated subcutaneously with Enh4 (10 mg/kg/day) for 7 days. Changes in blood pressure and vascular function were assessed via radiotelemetry and wire myography respectively. In WKY VSMCs, Enh3 reduced basal ERK1/2 phosphorylation (26.8 ± 5.9% vs veh,), an effect absent in SHRSP VSMCs, while Enh4 had no effect. Only in SHRSP VSMCs, Enh3, but not Enh4, reduced basal AKT phosphorylation (63.5 ± 8.9% vs veh). Enh4, but not Enh3, reduced basal MLC20 phosphorylation (54.9 ± 7.5% vs veh) in WKY but not in SHRSP VSMCs. ET-1-induced Ca2+ influx in WKY and SHRSP VSMCs was unaffected by Enh3 and Enh4. Assessment of Ca2+ -independent contractile mechanisms in VSMCs showed that ROCK2 activity is increased in SHRSP compared to WKY VSMCs (WKY: 0.27 ± 0.05; SHRSP:4.78 ± 0.34) and Enh4, but not Enh3, reduced ROCK2 activity in SHRSP VSMCs (61.5 ± 0.43% vs veh). Enh4 treatment in SHRSP rats reduced daytime systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP) (SBP:4.26 ± 1.98; DBP:1.48 ± 0.92; MAP:2.07 ± 0.99 vs veh) compared to baseline. Furthermore, Enh4 treatment reduced U46619 induced contraction in SHRSP rat vessels (Emax(Mn): Veh- 13.16 ± 1.81; Enh4- 9.48 ± 1.31). Taken together, enhancing Mas1:ETBR interaction attenuates mitogenic and contractile signaling pathways in WKY and SHRSP VSMCs, and does not increase Ca2+ signaling, important in VSMC contraction. Enhancing Mas1:ETBR interaction reduces blood pressure and improves vascular function in SHRSP rats. Hence, Mas1:ETBR enhancers may be of potential therapeutic use as a new vasoprotective strategy to improve vascular function and to reduce blood pressure in hypertension.

Citronellal Attenuates Oxidative Stress–Induced Mitochondrial Damage through TRPM2/NHE1 Pathway and Effectively Inhibits Endothelial Dysfunction in Type 2 Diabetes Mellitus

In type 2 diabetes mellitus (T2DM), oxidative stress induces endothelial dysfunction (ED), which is closely related to the formation of atherosclerosis. However, there are few effective drugs to prevent and cure it. Citronellal (CT) is an aromatic active substance extracted from citronella plants. Recently, CT has been shown to prevent ED, but the underlying mechanism remains unclear. The purpose of this study was to investigate whether CT ameliorated T2DM-induced ED by inhibiting the TRPM2/NHE1 signal pathway. Transient receptor potential channel M2 (TRPM2) is a Ca2+-permeable cation channel activated by oxidative stress, which damages endothelial cell barrier function and further leads to ED or atherosclerosis in T2DM. The Na+/H+ exchanger 1 (NHE1), a transmembrane protein, also plays an important role in ED. Whether TRPM2 and NHE1 are involved in the mechanism of CT improving ED in T2DM still needs further study. Through the evaluations of ophthalmoscope, HE and Oil red staining, vascular function, oxidative stress level, and mitochondrial membrane potential evaluation, we observed that CT not only reduced the formation of lipid deposition but also inhibited ED and suppressed oxidative stress-induced mitochondrial damage in vasculature of T2DM rats. The expressions of NHE1 and TRPM2 was up-regulated in the carotid vessels of T2DM rats; NHE1 expression was also upregulated in endothelial cells with overexpression of TRPM2, but CT reversed the up-regulation of NHE1 in vivo and in vitro. In contrast, CT had no inhibitory effect on the expression of NHE1 in TRPM2 knockout mice. Our study show that CT suppressed the expression of NHE1 and TPRM2, alleviated oxidative stress-induced mitochondrial damage, and imposed a protective effect on ED in T2DM rats.

Effect of benzoyl taurine dipotassium salt on coagulation, hemostasis and vascular activity in the microvasculature of the brain in violation of cerebral circulation

Cerebral circulation disorders (CCD) are one of the most common causes of mortality and disability in the population. Improving the microcirculation of brain tissue is one of the main directions in the treatment and prevention of CCD.Aim of the study was to evaluate the effect of a new derivative of hydroxybenzoic (salicylic) acid on neurological deficit, hemostasis and functional state of arterial pial vessels in the study of prostacyclin-synthetic activity and evaluation of NOmediated endothelial dysfunction in rats under experimental CCD conditions. Material and methods. The experiment was carried out on 50 Wistar rats, which were simulated for CCD by occlusion of common carotid arteries. Within 7 days after the operation, the animals received treatment according to the group: saline, C-60 (N-(3-hydroxybenzoyl)taurine dipotassium salt) and acetylsalicylic acid. After treatment, the activity of the prostacyclin-synthetic system was assessed by the reaction of pial vessels to indomethacin, endothelial dysfunction was estimated by tests with acetylcholine and L-NAME. The parameters of plasma and platelet hemostasis were also studied, and behavioral tests (open field, adhesion test, rotarod, Morris water maze, passive avoidance task) were used to assess neurological deficits in animals. Results. When studying the level of neurological deficit in animals with brain ischemia after a course of administration of the test compound, it was noted that in the treated groups, compared with the control group, there was a significant increase in motor and exploratory activity, improvement in sensory-motor function and coordination of movements (p &lt; 0.05). Also, in the group treated with the salicylic acid derivative, normalization of the parameters of platelet and plasma hemostasis, improvement of the functional state of the vascular endothelium was observed. According to the results of assessing the prostacyclin-synthesizing activity of the endothelium of the cerebral vessels, it follows that the test compound inhibits cyclooxygenase at a level comparable with effect of acetylsalicylic acid. Conclusions. A new derivative of salicylic acid, the dipotassium salt of N-(3-hydroxybenzoyl)taurine, reduces the severity of neurological deficit, improves hemostasis parameters and the functional state of cerebral vessels in rats with brain ischemia in the experiment.

Music improves the therapeutic effects of bevacizumab in rats with glioblastoma: Modulation of drug distribution to the brain.

BackgroundThe development of new methods for modulation of drug distribution across to the brain is a crucial step in the effective therapies for glioblastoma (GBM). In our previous work, we discovered the phenomenon of music-induced opening of the blood-brain barrier (OBBB) in healthy rodents. In this pilot study on rats, we clearly demonstrate that music-induced BBB opening improves the therapeutic effects of bevacizumab (BZM) in rats with GBM via increasing BZM distribution to the brain along the cerebral vessels.MethodsThe experiments were performed on Wistar male rats (200–250 g, n=161) using transfected C6-TagRFP cell line and the loud rock music for OBBB. The OBBB was assessed by spectrofluorometric assay of Evans Blue (EB) extravasation and confocal imaging of fluorescent BZM (fBZM) delivery into the brain. Additionally, distribution of fBZM and Omniscan in the brain was studied using fluorescent and magnetic resonance imaging (MRI), respectively. To analyze the therapeutic effects of BZM on the GBM growth in rats without and with OBBB, the GBM volume (MRI scans), as well as immunohistochemistry assay of proliferation (Ki67 marker) and apoptosis (Bax marker) in the GBM cells were studied. The Mann–Whitney–Wilcoxon test was used for all analysis, the significance level was p < 0.05, n=7 in each group.ResultsOur finding clearly demonstrates that music-induced OBBB increases the delivery of EB into the brain tissues and the extravasation of BZM into the brain around the cerebral vessels of rats with GBM. Music significantly increases distribution of tracers (fBZM and Omniscan) in the rat brain through the pathways of brain drainage system (perivascular and lymphatic), which are an important route of drug delivery into the brain. The music-induced OBBB improves the suppressive effects of BZM on the GBM volume and the cellular mechanisms of tumor progression that was accompanied by higher survival among rats in the GBM+BZM+Music group vs. other groups.ConclusionWe hypothesized that music improves the therapeutic effects of BZM via OBBB in the normal cerebral vessels and lymphatic drainage of the brain tissues. This contributes better distribution of BZM in the brain fluids and among the normal cerebral vessels, which are used by GBM for invasion and co-opt existing vessels as a satellite tumor form. These results open the new perspectives for an improvement of therapeutic effects of BZM via the music-induced OBBB for BZM in the normal cerebral vessels, which are used by GBM for migration and progression.

Experimental Evidence of Buyang Huanwu Decoction and Related Modern Preparations (Naoxintong Capsule and Yangyin Tongnao Granule) in Treating Cerebral Ischemia: Intestinal Microorganisms and Transcriptomics in Rats.

Background The traditional Chinese medicines of Buyang Huanwu decoction (BYHW), Naoxintong capsule (NXT), and Yangyin Tongnao granules (YYTN) have excellent effects in preventing and treating cerebrovascular disease and are widely tolerated by patients. However, their effects on middle cerebral artery occlusion (MCAO) remain unknown. Methods We evaluated gut microbiota alterations, the brain transcriptome, and nerve cell responses in rats with MCAO. Results Our results showed that BYHW, NXT, and YYTN not only effectively improved the damaged state of blood vessels in rats and restored nerve function, but also improved survival. Additional experiments showed that treatment with BYHW, NXT, and YYTN regulated the intestinal microflora. Transcriptome analyses showed that BYHW, NXT, and YYTN modulated the transcriptome of rats with MCAO. The common mechanism of the three prescriptions for the treatment of cerebral ischemia may be related to the intestinal flora regulation of 60S ribosomal protein L18 (Rpl18), eukaryotic translation initiation factor 3 subunit, Ras homolog family member C, G protein subunit gamma 13 (Gng13), and Gng10 genes, among which Rpl18 is the most important. In addition, the three prescriptions had great specificity as anticerebral ischemia targets. Moreover, BYHW, NXT, and YYTN mitigated MCAO-induced hyperactivation of microglia and astrocytes. Conclusion This study provides a foundation for further research on the mechanisms and treatment of IS. The results strongly suggest that key gut microbiota can be used to study functional genomics of brain, leading to novel discoveries about key genes involved in important biological processes.

New Thiazole Acetic Acid Derivatives: A Study to Screen Cardiovascular Activity Using Isolated Rat Hearts and Blood Vessels.

Cardiovascular diseases are one of the major causes of mortalities worldwide. In the present research, new synthetic derivatives of thiazole were studied using isolated hearts and blood vessels of rats. The heart and thoracic aorta were tested with six new synthesized thiazole acetic acid derivatives (SMVA-10, SMVA-35, SMVA-40, SMVA-41, SMVA-42 and SMVA-60), and the data obtained were statistically analyzed and compared. Isolated rat hearts were used to record the changes in developed tension and heart rate, while thoracic aortas were used to measure the contractile response, before and after treatments. Analysis of the results indicated a significant (p < 0.01) increase in developed tension with the addition of SMVA-35, SMVA-40, SMVA-41 and SMVA-42, which was augmented in the presence of adrenaline without affecting the heart rate. On the other hand, acetylcholine significantly decreased the developed tension, which was significantly reversed (p < 0.01) in the presence of compounds (SMVA-35 and SMVA-60). However, in the presence of SMVA-35 and SMVA-40, acetylcholine-induced bradycardia was significantly (p < 0.01) reduced. Furthermore, only SMVA-42 induced a dose-dependent contractile response in the isolated blood vessel, which was abolished in the presence of prazosin. Therefore, it can be concluded that some of the new synthesized thiazole derivatives exhibited promising results by raising the developed tension without changing the heart rate or blood vessel function, which could be helpful in failing heart conditions. However, more research is required to fully comprehend the function, mechanism and effectiveness of the compounds.

High-fidelity, simulation-based microsurgical training for neurosurgical residents.

Simulation is increasingly recognized as an important supplement to operative training. The live rat femoral artery model is a well-established model for microsurgical skills simulation. In this study, the authors present an 11-year experience incorporating a comprehensive, longitudinal microsurgical training curriculum into a Canadian neurosurgery program. The first goal was to evaluate training effectiveness, using a well-studied rating scale with strong validity. The second goal was to assess the impact of the curriculum on objective measures of subsequent operating room performance during postgraduate year (PGY)-5 and PGY-6 training. PGY-2 neurosurgery residents completed a 1-year curriculum spanning 17 training sessions divided into 5 modules of increasing fidelity. Both perfused duck wing and live rat vessel training models were used. Three modules comprised live microvascular anastomosis. Trainee performance was video recorded and blindly graded using the Objective Structured Assessment of Technical Skills Global Rating Scale. Eleven participants who completed the training curriculum and 3 subjects who had not participated had their subsequent operative performances evaluated when they were at the PGY-5 and PGY-6 levels. Eighteen participants completed 106 microvascular anastomoses during the study. There was significant improvement in 6 measurable skills during the curriculum. The mean overall score was significantly higher on the fifth attempt compared with the first attempt for all 3 live anastomotic modules (p < 0.001). Each module had a different improvement profile across the skills assessed. Those who completed the microvascular skills curriculum demonstrated a greater number of independent evaluations during superficial surgical exposure, deep exposure, and primary maneuvers at the PGY-5 and PGY-6 levels. High-fidelity microsurgical simulation training leads to significant improvement in microneurosurgical skills. Transfer of acquired skills to the operative environment and durability for at least 3 to 4 years show encouraging preliminary results and are subject to ongoing investigation.

Typical cutaneous small-vessel vasculitis induced by combined injection of antiphosphatidylserine/prothrombin complex antibody and anti-LAMP-2 antibody in normal rats.

We previously reported that IgA vasculitis and cutaneous arteritis could be dependently associated with the presence of the antiphosphatidylserine/prothrombin complex (anti-PS/PT) antibody and lysosomal-associated membrane protein-2 (LAMP-2). The copy number of LAMP-2 mRNA in skin tissue samples from rats with cutaneous vasculitis induced by intravenous administration of anti-PS/PT antibody after subcutaneous histone injection was significantly higher than in those without cutaneous vasculitis. We found LAMP-2 protein overexpression in neutrophils and vascular endothelial cells of the affected blood vessels in rats with cutaneous vasculitis induced by intravenous administration of anti-PS/PT antibody after cutaneous priming by histones. We found typical cutaneous small-vessel vasculitis in the skin of rats given intravenous injection of both anti-PS/PT antibody and anti-LAMP-2 antibody after cutaneous priming by histones. We suggested that the introduction of skin local histones and anti-PS/PT antibody in serum could move LAMP-2 to the cell surface of neutrophils and vascular endothelial cells, and that anti-LAMP-2 antibody could bridge these cells through antigen-specific binding in typical cutaneous small-vessel vasculitis.

The role of thiazole acetate derivatives on isolated heart and blood vessels in experimental rats

Background and objectivesThough various drugs are available in the market for cardiovascular diseases, search for an efficacious and patient friendly drug is an ongoing process. The effect of synthesized thiazole compounds on isolated rat heart and isolated rat blood vessel to determine their potential as newer therapeutic agents. Materials and methodsSix thiazole acetate compounds were examined for their function on isolated heart and blood arteries utilizing standardized experimental models after being characterized and identified in the laboratory. Anesthetized Wistar albino rats' hearts were removed and placed on a Langendorff setup. The percentage change in developed tension and heart rate owing to injecting each thiazole acetate compound in the developed tension and heart rate were seen and recorded in an isolated heart that was mounted in a retrograde fashion using Krebs Henseleit solution. Similarly, anesthetized rats' thoracic aortas were separated, and responses to the standard drug phenylephrine and different thiazole acetate derivatives were examined. The pharmacological effect of the specific thiazole compound was determined by the percentage change in contractile response. ResultEach of the six thiazole acetate derivatives was injected at 1 nM, 10 nM, 100 nM, 1 M, 10 M, and 100 M concentrations. All six (T1 to T6) chemicals investigated in the present study had no significant effect on developed tension or heart rate. There was a nosignificant change in the percentage contraction after injecting 1 nM 3 nM,10 nM, 30 nM, 100 nM, 300 nM, 1 M, 3 M, 10 M, and 30 M,100 M,300 M (cumulative dose) of T1, T3, T4, T5, and T6, while T2 (- ethyl-4-methyl-2-aminothiazole) showed contractile effect in the form of vasoconstrictor activity, which was 30 % of that produced by phenylephrine. Interpretation and conclusionThiazole acetate derivatives did not show any cardiovascular effects except ethyl-4-methyl-2-aminothiazole, which showed a slight vascular contractile response as compared to phenylephrine. A more thorough examination of the utilization of thiazole derivatives is required to establish their potential significance in the cardiovascular system.

Stimulation of the endogenous hydrogen sulfide synthesis restores constitutive nitric oxide synthesis and endothelium-dependent vasodilation in old rats

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Hydrogen sulfide (H2S) is a gas transmitter of endogenous origin, which has an important regulatory function in the human body. Endogenous H2S is synthesized by three enzymes, cistationine-β-synthase (CBS), cistationine-γ-liase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MTS), which is coupled to the activity of cysteine aminotransferase (CAT). CAT, CBS, and CSE are pyridoxal-5- phosphate (PLP)-dependent enzymes. It is known that with age the exchange of hydrogen sulfide is disturbed against the background of increasing oxidative and nitrosative stress. At the same time there is a decrease of constitutive synthesis of nitric oxide (NO). Recent studies show that hydrogen sulfide closely interacts with the NO system. Activation of H2S biosynthesis and restoration of its pools in tissues of old animals may be a promising direction of cardiovascular disease prevention. The aim of the current work was to study the effect of H2S-synthesizing enzymes cofactor pyridoxal-5-phosphate (PLP) on the endothelium-dependent relaxation of smooth muscle vessels in old rats, as well as the H2S content and cNOS activity in aortic tissues. Methods Old rats (22-24 months old) were PLP administered per os in dose of 0,7 mg per kg daily for 2 weeks.The content of hydrogen sulfide, activity of cNOS and iNOS was measured in aortic tissues.Vascular reactions were determined in experiments on isolated aortic strips. To clarify the role of either NO or H2S in the endothelium-dependent vasorelaxation, N-nitro-L-arginine methyl ester hydrochloride (L-NAME) (Sigma, USA, 27 mg/kg) or O-carboxymethylhydroxylamine (O-CMH) (50 mg/kg) (Sigma, USA) was injected intraperitoneally 30 min before sacrificing. Results We showed that the H2S content was 1.6 times lower in old rat aorta compared to adult ones. PLP administration for 2 weeks induced a significant increase of H2S content in aortic tissue of old rats (P&amp;lt;0.05). It was found that with aging, the activity of cNOS decreases by 3 times, and the stimulation of endogenous Н2S leads to an increase in the activity of this enzyme in the aortic tissues by 2.1 times as compared with those in old animals. At the same time, the activity of the iNOS enzyme with aging increases by 3.8 times, and after the introduction of PLP, it decreases almost halved. Also shown, that PLP significantly improved endothelium-dependent aortic smooth muscle relaxation in old rats. The amplitude of acetylcholine-induced relaxation which was significantly reduced in old rats was increased more than 2.5-fold. This effect was reversed by inhibitors of NO-synthase and 3-mercaptopyruvate sulfurtransferase indicating the involvement of NO and H2S in the improved endothelium-dependent vascular relaxation. Conclusions Thus, H2S acts as a regulator of the NO system that increases cNOS activity and NO synthesis in aortic tissue, which improves endothelium-dependent relaxation of aortic smooth muscle in aged rats.

P.149 High-fidelity simulation-based microsurgical training for neurosurgical residents

Background: Mastery of microsurgical skills requires regular hands-on practice. Simulation is increasingly recognized as an important supplement to operative training experience. The live rat femoral artery model is the gold standard model for microneurosurgical skills simulation. We present an 11-year experience incorporating simulation-based microsurgical training into an established Canadian neurosurgery program. Methods: Postgraduate year 2 (PGY-2) neurosurgery residents completed a one-year curriculum spanning 17 training sessions divided into 5 modules of increasing fidelity. Both perfused duck wing and live rat vessel training modules were used. Three modules comprised live microvascular anastomosis. Trainee performance was video recorded and blindly graded using the Objective Structured Assessment of Technical Skills Global Rating Scale. Results: Eighteen participants completed 107 microvascular anastomoses. There was significant improvement in six measurable skills during the curriculum. Mean overall score was significantly higher on the fifth attempt compared to the first attempt for all 3 live anastomotic modules (p&lt;0.001). Each module had a different improvement profile across the skills assessed. The greatest improvement was observed during artery-to-artery anastomosis. Conclusions: This high-fidelity microsurgical simulation curriculum demonstrated a significant improvement in the six microneurosurgical skills assessed, supporting its use as an effective teaching model. Transferability to the operative environment is actively being investigated.

Assessment of Thevetia neriifolia Juss. Toxicity as a Rodenticide in Wistar Rats

Problems of rodents cannot be over underlined as a household and agricultural pest, damaging the crops on the field and stored produce thereby reducing qualities of produce. Controlling rodents using physical, biological and chemical methods have resulted in a slow rate success, several dangers on humans, animals and environment, hence they are discouraged. Thevetia neriifolia has been found to be a rich source of pesticide substance that could be used in crop protection; thus, its powdered form could be used as a baseline for potential natural rodenticide bait. The rodenticide capability of Thevetia neriifolia was evaluated using 50 female Wistar rats weighing 80±10 g which were acclimatized for seven days. The rats were allotted to ten treatments, each replicated five times. There was a Standard Reference Feed (diet) (SRF). The test samples were milled (with 2 mm sieve) sun-dried seed (SS), sun-dried leaf (SL) and sun-dried stem bark (SB). Each sample was incorporated at 15%, 30% and 45% into the reference diets. The allotments were in a completely randomized design. Experimental rats were fed with separate diets and supplied water ad-libitum for seven days. Results showed significant differences (p&lt;0.05) in all the parameters. Rats on SS and SB at 45% inclusion levels had the lowest body weight reduction. Also, the lowest feed intake was observed in rats fed 45% SS, while those on 15% SL and SRF had the highest feed intake. Packed cell volume and hemoglobin were the only hematological parameters that differed significantly (p&lt;0.05) at 15% and 45% SL inclusion levels. The serum biochemical parameters were not affected by the treatments (p&gt;0.05). Organ sections (livers, hearts and kidneys) showed moderate congestion of sinusoids, multiple foci of mononuclear cells and congestion of renal blood vessels of rats on 45% SS inclusion level. No mortality or abnormal behavioural changes were observed among animals on SRF. Varying dietary inclusion levels of test samples resulted in rat mortalities which was attributed to cardiac glycosides. Rats on 45% SS died faster within 96 hours than those on corresponding inclusion levels of SB and SL which died after 216 hours. Therefore, Thevetia neriifolia has rodenticide capability and could be used as baits for rats.

Dickkopf-1 exerts protective effects by inhibiting PANoptosis and retinal neovascularization in diabetic retinopathy

Diabetic retinopathy (DR) is a key reason for legal blindness worldwide. Currently, it is urgently necessary to determine the etiology and pathological molecular mechanism of DR to search for resultful therapies. Dickkopf-1 (DKK1) is inhibitive for canonical Wnt signaling via negative feedback, and has been reported as a biomarker for DR. However, the related mechanisms are still unclear. In this work, our data showed that DKK1 was decreased in the vitreous tissues at an early stage of diabetes triggered by streptozotocin (STZ) injection in rats. We subsequently found that DKK1 intravitreal injection significantly ameliorated the physiological function of retina in STZ-challenged rats, accompanied by improved retinal structure. Surprisingly, our results indicated that DKK1 injection remarkably suppressed PANoptosis in retinal tissues of STZ-challenged rats with DR, as proved by ameliorated pyroptosis, apoptosis and necroptosis, which were mainly through the blockage of cleaved Gasdermin-D (GSDMD), Caspase-3 and receptor-interacting protein kinase-3 (RIPK3). Additionally, Wnt signaling including the expression of Wnt, β-catenin and LDL receptor-related protein 5/6 (LRP5/6) was also highly prohibited in retina of DKK1-injected rats with DR. Furthermore, retinal neovascularization and acellular vessel in DR rats were also considerably abolished after DKK1 injection, accompanied by reduced expression levels of retinal vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9). More in vitro experiments showed that DKK1 treatment markedly repressed the proliferative and migratory ability of endothelial cells via inhibiting angiogenesis-related molecules. Together, all our results broaden the knowledge of the correlation between DKK1 and DR, and then provide a novel therapeutic strategy for the suppression of management of DR.

Changes in Cardiac and Vascular Contractile Protein in a Rat Model of Heart Failure with Preserved Ejection Fraction

Heart failure is classified as heart failure with reduced ejection fraction (HFrEF) or heart failure with preserved ejection fraction (HFpEF). Although several therapies have been demonstrated to improve outcomes in patients with HFrEF, none benefit patients with HFpEF. The molecular mechanism that results in HFpEF is unknown and has been impacted by the lack of animal models, and thus, we tested the hypothesis that metabolic and hypertensive stress would result in a rat model of HFpEF. Fischer 344 rats (6mo old) were fed a high fat diet and L‐NAME in the drinking water for 4‐weeks. Invasive and noninvasive hemodynamics demonstrate that the treated animals develop HFpEF; treated animals (n=7) vs controls (n=6) have normal systolic function with LV hypertrophy (20.7±0.4mm v 27.6±2.1mm, p&lt;0.05) and diastolic abnormalities including a decrease in both E (79.4±3.6cm/s v 64.2±3.4cm/s, p=0.003) and dP/dtmin (‐7600±1100mmHg/s v ‐5600±1400mmHg/s, p=0.015), a steeper EDPVR (0.1±1.1mmHg/μl v 3.6±1.7mmHg/μl, p=0.042) and a slower time constant of relaxation (τ; 11±1ms v 16±2ms, p=0.029), as well as edema of the liver and lungs. Compared to controls, in cardiac muscle of HFpEF rats, there is no difference (p&gt;0.05) in the expression and/or phosphorylation of TnI or MyBPC. However, the expression of SERCA2 (p=0.021) and phosphorylation of phospholamban (p=0.046) are reduced, which would be expected to decrease the rate of SR Ca2+ reuptake and slow relaxation. In both the aorta and tertiary mesenteric vessels of HFpEF rats, the expression of nonmuscle myosin was significantly higher and the expression of the leucine zipper positive isoform of myosin light chain phosphatase was reduced, which should increase vascular tone and decrease the sensitivity of the vasculature to NO mediated vasodilatation. This study represents the first rat model of HFpEF and our results define a molecular mechanism that would contribute to both diastolic dysfunction and vascular abnormalities that characterize this disease. This rat HFpEF model could be used in future studies designed to delineate the mechanism(s) that produce the cardiac and vascular abnormalities that produce HFpEF and identify novel targets for rational drug design.

Influenza A Virus Causes Histopathological Changes and Impairment in Functional Activity of Blood Vessels in Different Vascular Beds.

It has been established that blood vessels are a target for influenza virus; however, the mechanism by which virus affects the cardiovascular system remains unknown. The aim of the study is the identification of histological changes and changes in the functional activity of the pulmonary and mesenteric blood vessels of Wistar rats. Wistar rats were intranasally infected with the influenza A(H1N1)pdm09 virus. At 24 and 96 h post infection (hpi), histopathological changes were observed in lung tissues with the absence of histological changes in mesenteric tissues. The functional activity of pulmonary and mesenteric arteries was determined using wire myography. In pulmonary arteries, there was a tendency towards an increase in integral response to the vasodilator and a decrease in the integral response to the vasoconstrictor at 24 hpi (compared with control). At 96 hpi, a tendency towards a decrease in the integral response to the vasoconstrictor persisted, while the response to acetylcholine was slightly increased. The functional activity of the mesenteric blood vessels was inverted: a significant decrease in the integral response to the vasodilator and an increase in the response to the vasoconstrictor at 24 hpi were observed; at 96 hpi, the integral response to the vasoconstrictor persisted, while the response to the vasodilator remained significantly reduced. Obtained data indicate the development of endothelial dysfunction in non-lethal and clinically non-severe experimental influenza virus infection.

Beneficial Impact of Interspecies Chimeric Renal Organoids Against a Xenogeneic Immune Response.

BackgroundAnimal fetal kidneys have the potential to be used as scaffolds for organ regeneration. We generated interspecies chimeric renal organoids by adding heterologous rat renal progenitor cells to single cells from mouse fetal kidneys and applying the renal development mechanism of mouse fetuses to rat renal progenitor cells to examine whether rat renal progenitor cells can differentiate into renal tissues of the three progenitor cell lineages of kidneys between different species. Furthermore, we investigated whether chimeric renal organoids with an increased proportion of recipient cells reduce xenogeneic rejection.MethodsC57BL/6JJmsSlc mice (B6 mice) and Sprague-Dawley-Tg (CAG-EGFP) rat (GFP rats) fetuses were used as donors, and mature male NOD/Shi-scid, IL-2RγKO Jic mice (NOG mice) and Sprague-Dawley rats (SD rats) were used as recipients. First, fetal kidneys were removed from E13.5 B6 mice or E15.5 GFP rats and enzymatically dissociated into single cells. These cells were then mixed in equal proportions to produce chimeric renal organoids in vitro. The chimeric organoids were transplanted under the renal capsule of NOG mice, and maturation of the renal tissues in the organoids was observed histologically. Furthermore, chimeric organoids were prepared by changing the ratio of cells derived from mouse and rat fetal kidneys and transplanted under the renal capsule of SD rats subjected to mild immunosuppression to pathologically analyze the strength of the xenogeneic immune response.ResultsThe cap mesenchyme was reconstructed in vitro, and nephron progenitor cells and ureteric buds were mosaically comprised GFP-negative mouse and GFP-positive rat cells. In the in vivo environment of immunodeficient mice, chimeric renal organoids mosaically differentiated and matured into renal tissues of three lineages. Chimeric renal organoids with high rates of recipient rat cells showed milder rejection than complete xenograft organoids. The vessels of recipient rats entered from the periphery of the transplanted chimeric renal organoids, which might reduce their immunogenicity.ConclusionInterspecies chimeric renal organoids may differentiate into mature renal tissues of each renal progenitor cell lineage. Furthermore, they may reduce transplant rejection compared with xenograft organoids.