Vessels Of Rats Research Articles

Effects of acetylsalicylic acid on histological structure of myocardial tissues in rats.

Acetylsalicylic acid has an antiplatelet effect and is used in long-term at low doses to prevent heart attacks, strokes and blood clot. The aim of the study was to investigate whether ASA could have pathological effects on heart tissues. Rats divided into three groups: Group 1 were given distilled water as controls, group 2 treated with ASA (500mg/Kg/d) by gastric gavage for 7 days and group 3 were received 500mg/Kg/d of ASA once daily for 7 days, then ASA was stopped for this group after 7 days and completed for a month. The histological sectioning of the control group was performed after 7 days and one month later, the second group after 7 days, and the third group after one month, then the result was observed. Histological examination of heart sections showed focal hyalinization in association with congestion in the myocardial blood vessels in rats treated with ASA for 7 days. While, sections of group three, revealed focal few inflammatory cells infiltration associated. It was concluded that, acetylsalicylic acid should be used only in limited amounts for limited periods as its signs of toxicity appeared even with its therapeutic dose.

未熟児網膜症モデルラットにおいて内皮依存性網膜血管拡張反応が減弱する

未熟児網膜症モデルラットにおいて内皮依存性網膜血管拡張反応が減弱する

PERBEDAAN ANGIOGENESIS PADA PULPA SETELAH APLIKASI EKSTRAK PROPOLIS DAN KALSIUM HIDROKSIDA

Background : Propolis is a resinous hive product collected by bees ( Apis Mellifera ) from tree buds and mixed with secreted bee wax in order to avoid bacterial contamination in the hive, and also to seal it. Propolis is employed for the treatment of various infectious diseases because it is wellknown that is has antibacterial and anti-inflammatory properties. Calcium hydroxide was introduced to the dental profession in 1921 and has been considered the “gold standard” for direct pulp capping materials in the past decades. Aims :This research is to investigate the development of new blood vessels ( angiogenesis ) in rat's dental pulp following application of propolis extract and calcium hydroxide. Methods : There was 43 Strain Wistar rats of 8–16 week old and 200–250 grams in weight were used in this study. The rats were randomly divided into 6 groups. Pulp exposures were performed on the occlusal surface of right maxillary first molars. At the 1st and 4th groups, as the control group, without pulp capping paste. At the 2rd and 5th groups, pulp exposure was applied with propolis extract. And at 3th and 6th groups pulp exposure was applied with calcium hydroxide ,and the 7th group is negative control is a normal teeth. Pulp exposure was applied with propolis extract. After that, all of the cavities were filled with light cured glass ionomer cement as a permanent filling. Animals on the 1st, 2rd, and 3th groups were decaputed after 7x24 hour post pulp capping material application and were sent for histological examination which new blood vessels ( angiogenesis ) cells were present. And at the 4th, 5th, 6th groups were culled after 7x 24 hour post pulp capping material application and were sent for histological examination which new blood vessels ( angiogenesis ) evaluated were present. Result : All sample were histopathological examinated and data was statiscally analysed using one way ANOVA the histological analysis revealed that the development of the new blood vessels occurred in all group. The new blood vessels ( angiogenesis ) of propolis extract group was milder compared to the control and calcium hydroxide group, with statistical analysis showed significant difference (p > 0.05). Conclusion: The development of new blood vessels is earlier happened in group capping material containing propolis and which show with reduce the amount of the new blood vessels in days 7 and 14 than the other group.

Effect of atorvastatin on LOX-1 and eNOS expression in collateral vessels of hypercholesterolemic rats

To investigate the effect of atorvastatin on the expression of lectin- like oxLDL receptor 1 (LOX-1) and endothelial nitric oxide synthase (eNOS) in collateral vessels of hypercholesterolemic rats. Forty male SD rats were randomized equally into 4 groups: femoral ligation group (L), hypercholesterolemia + femoral ligation group (HL), hypercholesterolemia+atorvastatin+femoral ligation group (AL), and hypercholesterolemia+normal saline+femoral ligation group (NL). The rats in the latter 3 groups were fed atherogenic diet for 8 weeks. At the end of the 8 weeks, the rats were subjected to femoral artery ligation with or without intraperitoneal injection of atorvastatin (AL group) or saline (NL group). Two weeks later, all the rats were euthanized and the expressions of LOX-1 and eNOS in the collateral vessels were detected with immunofluorescence assay. In the in vitro experiment, cultured human umbilical vein endothelial cells (HUVECs) were transfected with LOX-1 siRNA followed by treatment with oxLDL and/or atorvastatin. The expressions of LOX-1 and eNOS in the cells were detected with realtime PCR and Western blotting, and the cellular NO production was examined with Griess assay. The collateral vessels of rats with normal feeding expressed LOX-1, which was significantly increased in the collateral vessels of hypercholesterolemic rats; atorvastatin treatment significantly lowered LOX-1 expressions in the hypercholesterolemic rats. In normally fed rats, the growing collateral vessels exhibited strong eNOS expressions, which were lowered in hypercholesterolemic rats and enhanced after atorvastatin treatment. In the cell experiment, HUVECs with oxLDL treatment showed a high LOX-1 expression and a low eNOS expression, and atorvastatin treatment of the cells down-regulated LOX-1 and up-regulated eNOS expressions. Inhibition of LOX-1 mediated by a specific LOX-1 siRNA abolished the effect of oxLDL stimulation on eNOS expression in the cells. Both hypercholesterolemia and oxLDL can induce endothelial dysfunction and impair collateral vessel growth via the LOX-1/eNOS pathway in rats, and atorvastatin treatment can restore the LOX-1/eNOS pathway to promote the growth of the collateral vessels, suggesting the potential of atorvastatin as a therapeutic agent to promote repair of collateral vessel injuries in ischemic diseases.

Effect of Endomorphin-1 on Contractile Activity of Rat Mesenteric Lymphatic Vessels.

We studied the effect of endomorphin-1 on isolated mesenteric lymphatic vessels in rats. It was found that endomorphin-1 caused a dose-dependent increase in the contractile activity of lymphangions, which was associated with stimulation of intracellular calcium depots. The observed effect of endomorphin-1 in isolated lymphatic vessels has a complex mechanism; it depends on the concentration of the applied peptide and is probably determined by its interaction with non-opioid receptors.

The Occurrence of Physaloptera Hispida and a Mastophorus Sp. in Pulmonary Vessels of Hispid Cotton Rats ( Sigmodon hispidus) from Georgia, U.S.A.

During 2017-2018, a survey for the rat lungworm, Angiostrongylus cantonensis (Nematoda: Metastrongyloidea), in rodents from Piedmont and Lower Coastal Plains physiographic regions of Georgia was conducted. On 4 occasions, a single worm was recovered from the pulmonary vessels of a single cotton rat (Sigmodon hispidis). One of these worms was identified as a Physaloptera sp. and the remaining 3 as a Mastophorus sp. by morphology. No A. cantonensis were found. Physaloptera (Nematoda: Physalopteroidea) and Mastophorus species (Nematoda: Spiruroidea) are stomach parasites of many wild and domestic animals. This is the first report of these species in the pulmonary vessels of a definitive host. To better characterize these parasites, representative specimens were collected from cotton rat stomachs and identified morphologically and molecularly. Based on partial cytochrome c oxidase subunit 1 (COI) gene sequences, Physaloptera hispida from stomachs were identical to the Physaloptera sp. from the pulmonary vessels. The COI sequences from the Mastophorus sp. from the stomach exhibited a higher degree of variability but confirmed that the pulmonary worms were the same Mastophorus species. Furthermore, sequences of Mastophorus from a coastal site clustered separately from a clade of Mastophorus sequences from cotton rats from a Piedmont site. Our data show that adult worms recovered from pulmonary vessels of cotton rats could be either Physaloptera or Mastophorus sp., indicating that these parasitic worms are not always restricted to the stomach and that worms from pulmonary vessels must be carefully examined to obtain a definitive diagnosis of A. cantonensis infection.

Estrogen administration reduces the risk of pulmonary arterial hypertension by modulating the miR-133a signaling pathways in rats.

We aimed to investigate how estrogen (ES) is implicated in the pathogenesis of pulmonary arterial hypertension (PAH) potentially by reducing the extent of vascular remodeling in females. HE assay, Western Blot, IHC, and real-time PCR were carried out to observe the role of ES in regulating miR-133a expression and the levels of MYOSLID, SRF, CTGF, and vascular remodeling in rats. In addition, MTT assay and flow cytometry were utilized to observe how ES affects cell proliferation and cell cycle in PAH. Moreover, luciferase assays were carried out to clarity the regulatory relationship between miR-133a and its downstream targets. ES administration relieved the deregulation of miR-133a, MYOSLID, SRF, and CTGF in PAH rats. In addition, ES also reduced the thickening of blood vessels in PAH rats. ES could activate miR-133a promoter and arrest the cells in the G0/G1 cycle, thus dose-dependently suppressing the proliferation of cells. In addition, the presence of ES, MYOSLID siRNA, or miR-133a precursor all altered the expression of MYOSLID, SP1, SRF, and CTGF, thus establishing a molecular signaling pathway among these factors. Furthermore, miR-133a could bind to SP1, MYOSLID, SRF, and CTGF to reduce their expression. Moreover, SRF was proved to function as an activator of miR-133a promoter. Two feedback loops were established in this study: a negative feedback loop between SRF and miR-133a, and a positive loop among miR-133a/SRF/MLK1/MYOSLID. ES treatment upregulates miR-133a expression and reduces the incidence of PAH and vascular remodeling.

The effect of β-endorphin on the functional parameters of the isolated heart and lymphatic vessels of the white rat

Objective. The work is devoted to the comparison of the mechanisms of β-endorphin action in isolated rat heart and lymphatic vessels.
 Materials and methods. The experiments were performed using the Langendorff System perfusion device (Panlab, Spain) and the multichannel wire myograph 620M (DMT). During the study, selective opioid receptor blockers, K + channel blockers were used.
 Conclusion. In the course of experimental studies it was found that the most likely target for β-endorphin in an isolated rat heart are δ-opioid receptors, in isolated lymphatic vessels of a rat - μ- and δ-opioid receptors. The inhibitory effect of β-endorphin in the heart muscle is associated with stimulation of ATP-sensitive K + channels. In isolated lymphatic vessels, the effect of β-endorphin is realized through the activation of both potential-dependent and ATP-sensitive K+ channels.

Activation of transient receptor potential vanilloid 4 channels dilates rat retinal arterioles through nitric oxide- and BKCa channel-dependent mechanisms in vivo.

Transient receptor potential vanilloid 4 (TRPV4) channel, a cation channel expressed in nearly all cell types, plays an important role in the regulation of vascular tone. In the present study, we examined the effect of GSK1016790A, an activator of TRPV4 channels, on the diameter of retinal blood vessels in rats and the underlying mechanisms. Ocular fundus images were captured with an original high-resolution digital fundus camera in vivo and diameters of retinal blood vessels were measured. Intravenous infusion of GSK1016790A (0.2-2μgkg-1min-1) increased retinal arteriolar diameter in a dose-dependent manner. The higher dose of GSK1016790A (2μgkg-1min-1) slightly decreased blood pressure. These responses to GSK1016790A were significantly attenuated by intravenous injection of GSK2193874 (0.3mg/kg), an antagonist of TRPV4 channels. Intravitreal injection of Nω-nitro-L-arginine methyl ester, an inhibitor of nitric oxide (NO) synthase or iberiotoxin, an inhibitor of large-conductance Ca2+-activated K+ (BKCa) channel, significantly attenuated the GSK1016790A-induced increases in retinal arteriolar diameter. These results suggest that activation of TRPV4 channels dilates rat retinal arterioles through NO- and BKCa channel-dependent mechanisms in vivo.

The Effect of Dayak Onion Bulb Ethanol Extract (Sisyrinchium palmifolium L.) on Triglyceride Level and Aorta Histopathology in Diabetes Melitus White Rat Induced by Alloxan

The high prevalence of diabetes mellitus in Indonesia has made antidiabetic treatment efforts increasingly popular. In addition, the many side effects caused by the use of chemical drugs, triggered the development of research on herbal therapy. The purpose of this study was to determine the effectiveness of Dayak onion bulb extract in reducing two-hour postprandial blood glucose, triglyceride levels, and the amount of lipid vacuoles in aorta blood vessels of diabetic rat. The long-term goal of this study is the creation of innovation products in the form of standardized herbs as complementary therapies that can be used daily by the community, so that the risk of morbidity can be reduced. The research design used was randomized control group pretest posttest design. The results of blood glucose analysis showed that there were significant differences between the positive control group with the 400 mg/KgBW and 800 mg/KgBW extract group, with a significance value of 0,000. In the extract group, 400 mg/KgBW with 800 mg/KgBW extract group showed no significant difference with a significance value of 0.390. The results of the analysis of triglyceride levels showed no significant difference between the positive control group with the 400 mg/KgBW extract group, with a significance value of 0.981. However, there were significant differences between the positive control group with the 800 mg/KgBW extract group with a significance value of 0.025. Between the 400 mg/KgBW and 800 mg/KgBW extract groups, there was a difference with a significance value of 0.024. Aorta histopathology results showed that there was a significant difference in the number of lipid vacuoles between the positive control group and the 400 mg/KgBW extract group and 800 mg/KgBW extract group. Based on the research, it can be concluded that the extract dose of 400 mg/KgBW is a dose that is able to influence the decrease in blood glucose levels, triglycerides and the amount of lipid vacuoles in the aorta blood vessels.

Structural and functional peculiarities of the endothelium of heart vessels of mature rats according to immunistochemical studies

The relevance of the study is connected with the modern point of view that endothelial dysfunction may be the cause of such socially significant diseases as atherosclerosis, diabetes, varicose veins, etc. The aim of the work is to study the morphofunctional peculiarities of the endothelium of the cardiovascular vessels of the mature rat using Willebrand factor (vWF) immunohistochemistry.Material and methods. We used mature Wistar rats (n = 12). Polyclonal rabbit antibodies were used for the immunohistochemical detection of vWF. The reaction was carried out on paraffin sections, made through the whole heart.Results. It was shown that the immunopositive reaction to vWF (vWF+ ) in the endothelium of different regions of the rat heart is not uniform. A tendency was found to weaken the vWF+ reaction in the direction from the base of the heart to its apex. Most functionally active endothelial cells with signs of exocytosis were observed in the aortic root, the large coronary arteries of the epicardium, the fibrous ring, the valves and the subaortal cone. vWF+ was less pronounced in the endothelium lining the atrial and ventricular cavities and in the myocardial capillaries.Conclusions. Using immunohistochemical detection of the vWF, the endothelium features of different parts of the rat heart were identified. Structural features due to increased secretion of vascular endothelial cells of the heart were revealed. Further research in this direction may be important to explain the mechanisms and diagnosis of endothelial dysfunction.

Changes in the reactivity of vessels of rats with an experimental decrease in the mass of functioning nephrons

The aim : to evaluate changes in endothelium-dependent regulation of the tone of blood vessels (aorta and superior mesenteric artery) in rats 4 months after the removal of 5/6 renal tissue. Material and methods. An experimental CKD model was created by resection of 5/6 mass of renal tissue. The experimental group included animals (n = 12), subjected to nephrectomy (NE). The control group consisted of sham-operated (SO) rats (n = 10). Researches of vascular reactivity were performed on ring segments 2 mm long, which were excised from the aorta and superior mesenteric artery (SMA). A total of 23 segments of the aorta and 17 segments of SMA from rats after NE and 18 segments of the aorta and 15 segments of SMA from control animals were prepared. To measure the strength of contractions of the drugs, a FORT-10 sensor (WPI, USA) was used. The effects of acetylcholine (Ach, 1 x10 -6 M) on blood vessels, previously exposed to phenylephrine (1 x10 -5 M), and the response of vessels to Ach under conditions of prior exposure to TEA (1 x 10 -3 mol / l) and L-NAME (1 x10 -4 mol / l) were evaluated. Results. NE for a period of 4 months led to arterial hypertension - BP in the NE group of rats was higher (165, 0 ± 9.8 mm Hg) compared with SO (127.2 ± 9.7 mm Hg, р <0,001), and to myocardial remodeling (LVMI in NE rat was 2.72 ± 0.11 mg / g compared to 2.35 ± 0.09 mg / in the SO group, р <0,001 ). NE led to a decrease in dilatation of aortic and BWA fragments on the ACh compared with LO animals. Under the conditions of NO blocking, the NO synthase inhibitor — L-NAME — also had a lower response to ACh in rats with NE. The preliminary blockade of the Ca2 + -activated K + channels of high conductivity with the introduction of TEA resulted in a decrease in vasodilation caused by ACh in NE rat compared with the SO group. Conclusion. Resection of 5/6 of the kidney tissue mass in rats causes a decrease in vascular reactivity on the ACh. Endothelial dysfunction of rats after NE is associated with impairment of both NO-related and hyperpolarization-dependent endothelial cells in pathways of the vascular tone regulation.

Formic acid up-regulates vascular tension through nitric oxide-cGMP signaling pathway

Formic acid is a common organic acid used in many industrial processes. There is a paucity of research on the direct toxicity of formic acid and how it might affect the cardiovascular system. This study aimed to understand the effect of formic acid on vascular tension in an animal model and the underlying mechanism. Results found that the vasodilation induced by formic acid was related to the endothelium. When the dosage of formic acid was 1 mM or 5 mM, the vasodilation of endothelium-intact rings was partially suppressed by l-NAME, NS-2028 and nifedipine, and vasoconstriction caused by CaCl2 was inhibited, and the mRNA levels of eNOS, the activity of NOS (tNOS, iNOS and cNOS) and the level of NO and cGMP were significantly increased. Results also found that eNOS protein expression was significantly enhanced by 5 mM of formic acid. These results suggest formic acid can relax the aortic vessels of rats in a dose-dependent pattern. Further, the mechanism of the formic acid-induced vasodilatation likely involved the NO/cGMP pathway. Finally, the current study has revealed that vasodilation induced by high concentrations of formaldehyde may be the effect of the metabolite formic acid. This study will help further inform the etiologies of formic acid-related angiocardiopathies.

Effect of thrombin injection on cerebral vascular in rats with subarachnoid hemorrhage.

ObjectiveTo evaluate the effect of thrombin (TM) injection via the cerebellomedullary cistern on cerebral vessels in rats with subarachnoid hemorrhage (SAH).MethodsEighteen rats were randomly divided into three groups. In the A1 group, physiological saline was injected via the cerebellomedullary cistern; in the A2 group, 3 U of TM was injected into the subarachnoid space; and in the A3 group, SAH models were established and 3 U of TM was injected with the first injection of whole blood. Three days later, basilar artery specimens were collected for pathological examination.ResultsThe basilar arterial lumen cross-sectional area was significantly smaller in the A2 versus the A1 group, and proteinase-activated receptor (PAR)-1 and tumor necrosis factor (TNF)-α average optical densities were significantly higher (all P < 0.05). Basilar arterial lumen cross-sectional areas were significantly smaller in the A3 than the A2 group and average TNF-α optical densities were significantly lower (both P < 0.05), while those of PAR-1 did not differ significantly.ConclusionsThere was no significant difference in the extent of cerebral vasospasm between SAH and non-SAH model groups following TM injection into the subarachnoid space, so TM was considered to be an independent factor affecting cerebral vasospasm.

Tyrosine kinase inhibitors relax pulmonary arteries in human and murine precision-cut lung slices

BackgroundTyrosine kinase inhibitors (TKIs) inhibit the platelet derived growth factor receptor (PDGFR) and gain increasing significance in the therapy of proliferative diseases, e.g. pulmonary arterial hypertension (PAH). Moreover, TKIs relax pulmonary vessels of rats and guinea pigs. So far, it is unknown, whether TKIs exert relaxation in human and murine pulmonary vessels. Thus, we studied the effects of TKIs and the PDGFR-agonist PDGF-BB in precision-cut lung slices (PCLS) from both species.MethodsThe vascular effects of imatinib (mice/human) or nilotinib (human) were studied in Endothelin-1 (ET-1) pre-constricted pulmonary arteries (PAs) or veins (PVs) by videomicroscopy. Baseline initial vessel area (IVA) was defined as 100%. With regard to TKI-induced relaxation, K+-channel activation was studied in human PAs (PCLS) and imatinib/nilotinib-related changes of cAMP and cGMP were analysed in human PAs/PVs (ELISA). Finally, the contractile potency of PDGF-BB was explored in PCLS (mice/human).ResultsMurine PCLS: Imatinib (10 μM) relaxed ET-1-pre-constricted PAs to 167% of IVA. Vice versa, 100 nM PDGF-BB contracted PAs to 60% of IVA and pre-treatment with imatinib or amlodipine prevented PDGF-BB-induced contraction. Murine PVs reacted only slightly to imatinib or PDGF-BB. Human PCLS: 100 μM imatinib or nilotinib relaxed ET-1-pre-constricted PAs to 166% or 145% of IVA, respectively, due to the activation of KATP-, BKCa2+- or Kv-channels. In PVs, imatinib exerted only slight relaxation and nilotinib had no effect. Imatinib and nilotinib increased cAMP in human PAs, but not in PVs. In addition, PDGF-BB contracted human PAs/PVs, which was prevented by imatinib.ConclusionsTKIs relax pre-constricted PAs/PVs from both, mice and humans. In human PAs, the activation of K+-channels and the generation of cAMP are relevant for TKI-induced relaxation. Vice versa, PDGF-BB contracts PAs/PVs (human/mice) due to PDGFR. In murine PAs, PDGF-BB-induced contraction depends on intracellular calcium. So, PDGFR regulates the tone of PAs/PVs. Since TKIs combine relaxant and antiproliferative effects, they may be promising in therapy of PAH.

Reduced caveolae density in arteries of SHR contributes to endothelial dysfunction and ROS production

Caveolae are plasma membrane invaginations enriched with high cholesterol and sphingolipid content; they also contain caveolin proteins in their structure. Endothelial nitric oxide synthase (eNOS), an enzyme that synthesizes nitric oxide (NO) by converting L-arginine to L-citrulline, is highly concentrated in plasma membrane caveolae. Hypertension is associated with decreased NO production and impaired endothelium-dependent relaxation. Understanding the molecular mechanisms that follow hypertension is important. For this study, we hypothesized that spontaneously hypertensive rat (SHR) vessels should have a smaller number of caveolae, and that the caveolae structure should be disrupted in these vessels. This should impair the eNOS function and diminish NO bioavailability. Therefore, we aimed to investigate caveolae integrity and density in SHR aortas and mesenteric arteries and the role played by caveolae in endothelium-dependent relaxation. We have been able to show the presence of caveolae-like structures in SHR aortas and mesenteric arteries. Increased phenylephrine-induced contractile response after treatment with dextrin was related to lower NO release. In addition, impaired acetylcholine-induced endothelium-dependent relaxation could be related to decreased caveolae density in SHR vessels. The most important finding of this study was that cholesterol depletion with dextrin induced eNOS phosphorylation at Serine1177 (Ser1177) and boosted reactive oxygen species (ROS) production in normotensive rat and SHR vessels, which suggested eNOS uncoupling. Dextrin plus L-NAME or BH4 decreased ROS production in aorta and mesenteric arteries supernatant’s of both SHR and normotensive groups. Human umbilical vein endothelial cells (HUVECs) treated with dextrin confirmed eNOS uncoupling, as verified by the reduced eNOS dimer/monomer ratio. BH4, L-arginine, or BH4 plus L-arginine inhibited eNOS monomerization. All these results showed that caveolae structure and integrity are essential for endothelium-dependent relaxation. Additionally, a smaller number of caveolae is associated with hypertension. Finally, caveolae disruption promotes eNOS uncoupling in normotensive and hypertensive rat vessels and in HUVECs.

Optical coherence tomography angiography (OCT-A) in an animal model of laser-induced choroidal neovascularization

Aim of the study was to compare optical coherence tomography angiography (OCT-A) and conventional fluorescein angiography (FA) for quantitative analysis of the retinal and choroidal vasculature in the animal model of laser-induced choroidal neovascularization (CNV). Therefore, Dark Agouti rats underwent argon laser photocoagulation to induce CNV at D0. In vivo imaging using combined confocal scanner laser ophthalmoscopy (cSLO)-based FA and OCT-A (Heidelberg Engineering GmbH, Heidelberg, Germany) was performed before and immediately after laser treatment as well as at day 2, 7, 14 and 21. OCT-A en-face images were compared to cSLO images obtained by conventional FA topographic uptake recorded using a series of different pre-defined focus settings. For a quantitative comparison of CNV imaging by OCT-A and FA, CNV area, vessel density, number of vessel junctions, total vessel length and number of vessel end points were analyzed. Subsequent ex vivo analyses of the CNV included immunofluorescence staining of vessels in retinal and RPE/choroidal/scleral flatmount preparations. We found, that OCT-A allowed for high-resolution non-invasive imaging of the superficial, intermediate and deep retinal capillary plexus as well as the choroidal blood vessels in rats. Compared with OCT-A, visualization of CNV progression by invasive FA was less accurate, in particular the deep vascular plexus was visualized in more detail by OCT-A. The area of neovascularization was mainly detected in the deep retinal vascular plexus, outer nuclear layer (ONL), ellipsoid zone (EZ) and the choroid. Within the laser lesions, signs of CNV formation occurred at day 7 with progression in size and number of small vessels until day 21. Due to leakage and staining effects, CNV areas appeared significantly larger in FA compared to OCT-A images (p ≤ 0.0001 for all tested layers). Vessel density, number of vessel junctions, total vessel length and number of vessel end points were significantly higher in intermediate vascular plexus (IVP) and deep vascular plexus (DVP) in OCT-A compared to FA images. Overall, CNV area in flatmounts was similar to OCT-A results and much smaller compared to the area of dye leakage by FA. This study demonstrates that in vivo OCT-A imaging in small animals is feasible and allows for precise analysis of the formation of new blood vessel formation in the animal model of laser-induced CNV. Given its superior axial resolution, sensitivity and non-invasiveness compared to conventional FA imaging, OCT-A opens the door for a more detailed evaluation of CNV development in such a model and, thus, enables the analysis of the response to novel therapeutic interventions in longitudinal in vivo studies.

Beneficial Changes Promoted by L‐arginine and Aliskiren in Resistance Vessels in 2K1C hypertensive rats

Renovascular hypertension is characterized by increased angiotensin II and oxidative stress and by endothelial dysfunction. By acting on multiple targets and promoting diverse actions, angiotensin II (Ang II) plays a pivotal role in vascular dysfunction. The purpose of this study was to test whether the administration of aliskiren (ALSK) and L‐arginine (L‐arg) would restore endothelial dysfunction and reduce inflammation and oxidative stress in a rat renovascular hypertension model. Hypertension was induced by clipping the right renal artery, and the following five groups were divided: SHAM operated; 2‐kidney, 1‐clip (2K1C); 2K1C plus ALSK; 2K1C plus L‐ARG; and 2K1C plus ALSK+ L‐ARG. The vascular reactivity to norepinephrine (NE; 10(−9) to 2 × 10(−3) mol/L) and acetylcholine (ACh; 10(−10) to 10(−3) mol/L) was evaluated in the mesenteric arteriolar bed through concentration‐effect curves. The structure was assessed by histology and biomolecular analyzes were done via western blot, lipid peroxidation, DHE and DAF. For 4 weeks, blood pressure (BP) was monitored and endothelium‐dependent vasoconstriction and relaxation were assessed in mesenteric arteriolar. ALSK+L‐arg reduced BP and the contractile response to norepinephrine and improved acetylcholine relaxation. Incubation with N‐nitro‐L‐arginine methyl ester (L‐NAME) and L‐NAME+ Indometacin increased the response to norepinephrine in the 2K1C group and the effect was greater and partially improved, respectively, with the treatments. However, It was improved acetylcholine relaxation with the both of the treatments. The bioavailability of nitric oxide increased with the treatments, and the inflammation and oxidative stress was reduced with the treatments. L‐arginine and aliskiren attenuates the morphofunctional deleterious effects of Ang II on resistance vessels. The benefits of L‐arginine and aliskiren seem to occur through restoring the balance of ROS/NO. Therefore, this study opened new avenues for further clinical targeting of the treatment of cardiovascular diseases related to activation of the renin‐angiotensin system. In conclusion, combined ALSK+L‐arg treatment normalizes BP and prevents endothelial dysfunction in 2K1C hypertensive rats.Support or Funding InformationThis research was supported by a CNPq research grants. This study was funded by Fundação de Amparo a Pesquisa do Espirito Santo (FAPES‐Brazil) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq‐Brazil).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Contribution of the Renal Lymphatic Circulation to the Development of Salt‐Sensitive Hypertension

More than one billion people worldwide suffer from hypertension, which is a leading cause of stroke and cardiovascular disease. According to the National Heart, Lung, and Blood Institute (NHLBI) Working Group, an estimated 40% to 85% of hypertensive patients exhibit salt‐sensitivity, which increases the risk for cardiovascular events and mortality. Salt‐sensitive hypertension is known to be caused by an imbalance between sodium retention and excretion in the kidney. However, the mechanisms that enable the kidney to deliver excessive re‐absorbed salt and volume back to the systemic circulation remain obscure. Interestingly, recent studies indicate that the peripheral lymphatics act as a “salt sink” to store excessive salt and volume, thereby maintaining sodium homeostasis to regulate blood pressure. This finding led us to consider whether renal lymphatics contribute to excessive sodium retention in the kidney during the development of salt‐sensitive hypertension. To test this hypothesis, we initially evaluated lymph‐angiogenesis in the kidneys of rats with or without salt‐sensitive hypertension. Real‐time PCR, immunohistochemistry and Western blots revealed increased expression of the lymphatic‐specific marker VEGFR3 in the kidneys of Dahl salt‐sensitive (DSS) rats fed a high‐salt diet compared to either DSS rats fed regular chow or Dahl salt‐resistant (DSR) rats with or without high‐salt intake. To explore the impact of renal lymph‐angiogenesis on blood pressure, we surgically ligated the renal collecting lymph vessel (LV) in DSS rats. Ligation of the renal LV in DSS rats attenuated the increase in systolic blood pressure caused by a high‐salt diet. Notably, a growing body of evidence has implicated macrophages in lymph‐angiogenesis. Indeed, we also observed that a high‐salt diet promoted renal infiltration of macrophages, which stimulated renal lymph‐angiogenesis via upregulating VEGFR3 and its ligand VEGFC. Collectively, our data suggest that in response to a high‐salt diet, kidney‐infiltrated macrophages stimulate renal lymph‐angiogenesis, which appears to support the development of salt‐sensitive hypertension.Support or Funding InformationSupported by NIH grants T32 GM106999 (BRG) and R21 CA187325‐01A1 (NJR), and a Medical Research Endowment Award (SM) from the Univ. of Arkansas for Medical Sciences.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Prostaglandin E2 at low concentrations dilates whereas at higher concentrations constricts human cerebral parenchymal arterioles: implications for neurovascular coupling responses

There is considerable controversy regarding the vasoactive action of prostaglandin E2 (PGE2). On the one hand, indirect evidence implicates that astrocytic release of PGE2 contributes to neurovascular coupling responses mediating functional hyperemia in the brain. On the other hand, overproduction of PGE2 was also reported to contribute to cerebral vasospasm associated with subarachnoid hemorrhage. The present study was conducted to resolve this controversy by determining the direct vasoactive effects of PGE2 in resistance‐sized human cerebral parenchymal arterioles.To achieve this goal PGE2‐induced isotonic responses were assessed in parenchymal arterioles isolated from fronto‐temporo‐parietal cortical tissues surgically removed from patients and expression of PGE2 receptors were examined.In functionally intact parenchymal arterioles lower concentrations of PGE2 (from 10−8 to 10−6 mol/l) caused significant, endothelium‐independent vasorelaxation, which was inhibited by the EP4 receptor blocker BGC201531. In contrast, higher concentrations of PGE2 evoked significant EP1‐dependent vasoconstriction, which could not be reversed by the EP4 receptor agonist CAY10598. We also confirmed previous observations that PGE2 primarily evokes constriction in intracerebral arterioles isolated from R. norvegicus. Importantly, vascular mRNA expression of vasodilator EP4 receptors was significantly higher than that of vasoconstrictor EP1 receptors in human cerebral arterioles. In contrast, rat vessels expressed predominantly EP1 receptors.PGE2 at low concentrations dilates whereas at higher concentrations constricts human cerebral parenchymal arterioles. This bimodal vasomotor response is consistent with both the proposed vasodilator role of PGE2 during functional hyperemia and its putative role in cerebral vasospasm associated with subarachnoid hemorrhage in human subjects.Support or Funding InformationThis work was supported by grants from the National Research, Development and Innovation Office to PT (NKFI‐FK123798) and AK (K108444), the Hungarian Academy of Sciences Bolyai Research Scholarship BO/00634/15 to PT, the PTE AOK‐KA 3/2016 04.01/F to PT, the ÚNKP‐18‐4‐PTE‐6 New National Excellence Program of the Ministry of Human Capacities, Higher Education Institutional Excellence Programme – Grant No. 20765‐3/2018/FEKUTSTRAT, EFOP‐3.6.2.‐16‐2017‐00008, GINOP‐2.3.2‐15‐2016‐00048 and GINOP‐2.3.3‐15‐2016‐00032 to PT and AB, the Hungarian National Brain Research Program Grant No. 2017‐1.2.1‐NKP‐2017‐00002 to AB; the Marie Curie Actions SMARTER 7th Framework Program of the European Union 606998 to NSz and AK, National Institute of Health R01‐AG055395, R01‐NS100782, R01‐AT006526 to ZU.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.