Vein Of Rats Research Articles

Important role of the SDF-1/CXCR4 axis in the homing of systemically transplanted human amnion-derived mesenchymal stem cells (hAD-MSCs) to ovaries in rats with chemotherapy-induced premature ovarian insufficiency (POI)

BackgroundChemotherapy can induce premature ovarian insufficiency (POI). POI causes multiple sequelae and is currently incurable. As shown in our previous studies, systemically transplanted human amnion-derived mesenchymal stem cells (hAD-MSCs) home to ovaries with chemotherapy-induced POI and subsequently reduce ovarian injury and improve ovarian function in rats with POI. However, the cellular mechanisms that direct the migration and homing of hAD-MSCs to ovaries with chemotherapy-induced POI are incompletely understood. This study investigated the role of the SDF-1/CXCR4 axis in the migration and homing of systemically transplanted hAD-MSCs to ovaries with chemotherapy-induced POI and its relevant downstream signalling pathways.MethodsCXCR4 expression in hAD-MSCs was assessed using Western blotting and immunofluorescence staining. hAD-MSC migration was tested using Transwell migration assays. SDF-1 levels were detected using ELISA. Seventy-two female SD rats were randomly divided into the control, POI, hAD-MSCs and hAD-MSCs + AMD3100 groups. Cyclophosphamide was used to establish rat POI models. For inhibitor treatment, hAD-MSCs were pretreated with AMD3100 before transplantation. PKH26-labeled hAD-MSCs were injected into the tail vein of POI rats 24 h after chemotherapy. After hAD-MSC transplantation, the homing of hAD-MSCs to ovaries and ovarian function and pathological changes were examined. We further investigated the molecular mechanisms by detecting the PI3K/Akt and ERK1/2 signalling pathways.ResultshAD-MSCs expressed CXCR4. SDF-1 induced hAD-MSC migration in vitro. SDF-1 levels in ovaries and serum were significantly increased in rats with chemotherapy-induced POI, and ovaries with POI induced the homing of hAD-MSCs expressing CXCR4. Blocking the SDF-1/CXCR4 axis with AMD3100 significantly reduced the number of hAD-MSCs homing to ovaries with POI and further reduced their efficacy in POI treatment. The binding of SDF-1 to CXCR4 activated the PI3K/Akt signalling pathway, and LY294002 significantly inhibited hAD-MSC migration induced by SDF-1 in vitro. Moreover, inhibition of the PI3K/Akt signalling pathway significantly reduced the number of systemically transplanted hAD-MSCs homing to chemotherapy-induced ovaries in rats with POI.ConclusionsSDF-1/CXCR4 axis partially mediates the migration and homing of systemically transplanted hAD-MSCs to the ovaries of rats with chemotherapy-induced POI, and the PI3K/Akt signalling pathway might be involved in the migration and homing of hAD-MSCs mediated by the SDF-1/CXCR4 axis.

Repetitive Blood Sampling from the Subclavian Vein of Conscious Rat.

Rats are widely used in pharmacokinetics (PK) and toxicokinetic (TK) studies that need to collect a certain amount of blood at specific time points to detect drug exposure. The rat blood sampling method determines the quality of the plasma and further affects the precision of the test results. The subclavian vein blood collection method described in this protocol collects blood samples repeatedly in the conscious state of animals to meet the needs of PK and TK tests. The skills of restraint handling and appropriate procedure of needle incision ensure the success rate of blood collection. It is easy to operate while ensuring the quality of plasma and at the same time catering to animal welfare. However, this method requires skilled operation, and an improper one may cause animal weakness, pain, lameness, and even mortality. The current method has been used in the testing facility for a 4-week oral toxicity study in Sprague Dawley (SD) rats with TK. The maximum amount of blood collected within 24 h did not exceed 20% of the animal's total blood. The animals' body weight was more than 200 g for males and females. The data showed that the animals' bodyweight increased steadily every week, and the clinical observation was normal after repetitive sample collection.

Repetitive Blood Sampling from the Subclavian Vein of Conscious Rat

Rats are widely used in pharmacokinetics (PK) and toxicokinetic (TK) studies that need to collect a certain amount of blood at specific time points to detect drug exposure. The rat blood sampling method determines the quality of the plasma and further affects the precision of the test results. The subclavian vein blood collection method described in this protocol collects blood samples repeatedly in the conscious state of animals to meet the needs of PK and TK tests. The skills of restraint handling and appropriate procedure of needle incision ensure the success rate of blood collection. It is easy to operate while ensuring the quality of plasma and at the same time catering to animal welfare. However, this method requires skilled operation, and an improper one may cause animal weakness, pain, lameness, and even mortality. The current method has been used in the testing facility for a 4-week oral toxicity study in Sprague Dawley (SD) rats with TK. The maximum amount of blood collected within 24 h did not exceed 20% of the animal's total blood. The animals' body weight was more than 200 g for males and females. The data showed that the animals' bodyweight increased steadily every week, and the clinical observation was normal after repetitive sample collection.

Hepatic processing of mercuric ions facilitates delivery to renal proximal tubules

Mercury (Hg) is a toxic heavy metal to which humans are exposed on a regular basis. Hg has a high affinity for thiol-containing biomolecules with the majority of Hg in blood being bound to albumin. The current study tested the hypothesis that circulating Hg-albumin complexes are taken up into hepatocytes and processed to form Hg-glutathione (GSH) conjugates (GSH-Hg-GSH). Subsequently, GSH-Hg-GSH conjugates are exported from hepatocytes into blood via multidrug resistance transporters (MRP) 3 and 5. To test this hypothesis, the portal vein and hepatic artery in Wistar rats were ligated to prevent delivery of Hg to the liver. Ligated and control rats were injected with HgCl2 or GSH-Hg-GSH (containing radioactive Hg) and the disposition of Hg was assessed in various organs. Renal accumulation of Hg was reduced significantly in ligated rats exposed to HgCl2. In contrast, when rats were exposed to GSH-Hg-GSH, the renal accumulation of Hg was similar in control and ligated rats. Experiments using HepG2 cells indicate that Hg-albumin conjugates are taken up by hepatocytes and additional experiments using inside-out membrane vesicles showed that MRP3 and MRP5 mediate the export of GSH-Hg-GSH from hepatocytes. These data are the first to show that Hg-albumin complexes are processed within hepatocytes to form GSH-Hg-GSH, which is, in part, exported back into blood via MRP3 and MRP5 for eventual excretion in urine.

Effect of ethylmethylhydroxypyridine succinate on the functional activity of the transporter P-glycoprotein in the blood-brain barrier of rats under normal conditions and under hypoxic hypoxia

Relevance. Ethylmethylhydroxypyridine succinate (EMHPS) is a reference domestic drug with pronounced antioxidant and antihypoxic activity. P-Glycoprotein (Pgp) is an ATP-dependent transport protein localized in tissue barriers and protecting cells and organs from the effects of xenobiotics. Being expressed in the blood-brain barrier (BBB), Pgp limits the penetration of drugs and toxic substances into the brain tissue. Aim – to evaluate the effect of EMHPS on the functional activity of Pgp in the BBB of rats in normal conditions and in acute hypoxic hypobaric hypoxia in the experiment. Methods. The studies were carried out on male Wistar rats weighing 200–250 g, which were divided into 4 groups: group 1 (control, n = 30) – intact rats; Group 2 (control of hypoxia, n = 30) – rats, which were simulated hypoxia and before that they were once injected with water for injection; Group 3 (n = 30) – intact animals, which were injected intravenously with EMHPS at a dose of 50 mg / kg body weight; Group 4 (n = 30) – rats, which were injected intravenously with EMHPS at a dose of 50 mg/kg body weight before modeling hypoxia. 30 minutes after injection, animals of groups 2 and 4 were simulated acute hypoxic hypoxia for 30 minutes by ascending to an altitude of 8000 m with an ascent and descent speed of 50 m/s. 3 h after descent animals of groups 2 and 4 and 30 min after intravenous injection in animals of groups 1 and 3, the functional activity of Pgp in the BBB was assessed by the penetration of fexofenadine, a marker substrate of Pgp, into the brain tissue. For this, fexofenadine was injected into the tail vein of rats at a dose of 10 mg/kg of body weight. After 5, 10, 15, 30, 45, 60 minutes after administration, they were euthanized, at least 4 ml of blood was taken from the abdominal aorta into heparinized tubes and the cortex of the frontal lobes of the brain. The concentration of fexofenadine in biosamples was analyzed by HPLC-UV according to original methods. Results. In the course of the study, it was shown that a single intravenous injection of EMHPS at a dose of 50 mg/kg of body weight causes an increase in the content of fexofenadine in the cerebral cortex of rats, which indicates a decrease in the activity of the Pgp transporter protein. Simulation of acute hypoxic hypoxia was also accompanied by an increase in the permeability of the transport protein substrate into the brain tissue. At the same time, the prophylactic administration of EMHPS before hypoxic exposure did not significantly affect the BBB permeability, which remained significantly higher than the control and did not differ from the permeability during isolated hypoxic exposure. Conclusions: EMHPS with a single intravenous injection at a dose of 50 mg/kg body weight reduces the activity of Pgp in the BBB in normal conditions and does not significantly affect the penetration of the transporter substrate – fexofenadine into the brain tissue in acute hypoxic hypoxia

Biomimetic peptide nanoparticles participate in natural coagulation for hemostasis and wound healing.

Uncontrolled hemorrhage is a major problem both in surgical intervention and after trauma. Herein, we design an in situ constructable peptide network, mimicking and participating in the native coagulation process for enhanced hemostasis and wound healing. The network consists of two peptides including C6KL, mimicking platelets and C6KG, mimicking fibrin. The C6KL nanoparticles could bind to the collagen at the wound site and transform into C6KL nanofibers. The C6KG nanoparticles could bind to GPIIb/IIIa receptors on the surface of activated platelets and transform into C6KG nanofibers. The in situ formed peptide network could interwind platelets, fibrin and red blood cells, causing embolism at the wound site. In a lethal femoral artery, vein, and nerve cut model of rats, the amount of bleeding was reduced to 32.8% by C6KL and C6KG with chitosan/alginate. The biomimetic peptides show great clinical potential as trauma hemostatic agents.

Light Microscopic Study on Possible Protective Effect of Vitamin E on Imatinib IHCV Dilatation in Albino Rats

Aim: To observe the changes in the caliber of hepatic central vein of Albino rats exposed to the oral administration of toxic doses of Imatinib and to assess the protective effect of vitamin E. Study design: Experimental study Place and duration of study: Department of Pharmacy, Peshawar Medical College Peshawar from 1st October 2015 to 31st March 2016. Methodology: Twenty four male Sprague-Dawley rats (150- 200g) were selected for this study and these rats were divided into three groups. Group 1 was control group, Group II received oral Imatinib solution (50 mg/kg/day) and Group III received Imatinib solution (50mg/kg/day) orally along with vitamin- E (500MG/kg/day) for 14 days. At the end of experiment central vein dilatation in liver tissue of rats were observed. Results: The increase in mean central vein dilatation in liver of group II were statistically significant (p=0.001) in comparison with the control. The mean central vein caliber of liver was decreased significantly in group III. Conclusion: The simultaneous use of vitamin E as an antioxidant with Imatinib can protect the toxic effects of the Imatinib on hepatic toxicity which includes central vein dilatation. Keywords: Imatinib mesylate, Hepatic tissue, Central vein dilatation, Vitamin E

Monitoring of Cardiorespiratory Parameters in Rats-Validation Based on Pharmacological Stimulation.

The methods used in preclinical studies should minimize the suffering and the number of animals but still provide precise and consistent results enabling the introduction of drug candidates into the phase of clinical trials. Thus, we aimed to develop a method allowing us to perform preliminary safety and toxicity studies of candidates for human medicines, while reducing the number of animals. We have devised a method based on a combination of two devices: Plugsys (Transonics System Inc., Ithaca, NY, USA) and PhysioSuite (Kent Scientific Corporation, Torrington, CT, USA), which allow simultaneous registration of nine circulatory and respiratory parameters, and body temperature. Vehicle and adrenaline, or nitroglycerin, as reference substances were administered into the right femoral vein of Wistar rats. Physiological conditions were registered over 60 min after drug administration by measuring systolic, diastolic and mean blood pressure, heart rate (HR), blood perfusion of paw vessels, blood oxygen saturation, respiratory rate, average and peak exhaled CO2, and body temperature. Blood pressure was measured by cannula placed in the left common carotid artery and connected to the pressure transducer (Plugsys). The other parameters were measured by the PhysioSuite. Adrenaline-induced immediate dose-related hypertension and nitroglycerin hypotension were correlated with the change in blood perfusion. They both increased HR. Adrenaline decreased blood oxygen saturation and slightly affected respiratory parameters, while nitroglycerin caused a progressive increase in respiratory rate and a decrease in the peak of exhaled CO2. Our method may become an inseparable part of the preliminary safety and toxicity studies of tested drugs, while being an important step towards improving animal welfare.

MiR-190-5p Alleviates Myocardial Ischemia-Reperfusion Injury by Targeting PHLPP1.

Objective Myocardial ischemia-reperfusion (I/R) injury (MIRI) refers to the more serious myocardial injury after blood flow recovery, which seriously affects the prognosis of patients with ischemic cardiomyopathy. This study explored the new targets for MIRI treatment by investigating the effects of miR-190-5p and its downstream target on the structure and function of myocardial cells. Methods We injected agomir miR-190-5p into the tail vein of rats to increase the expression of miR-190-5p in rat myocardial cells and made an I/R rat model by coronary artery occlusion. We used 2,3,5-triphenyl tetrazolium chloride staining, lactate dehydrogenase (LDH) detection, echocardiography, and hematoxylin-eosin (HE) staining to determine the degree of myocardial injury in I/R rats. In addition, we detected the expression of inflammatory factors and apoptosis-related molecules in rat serum and myocardial tissue to determine the level of inflammation and apoptosis in rat myocardium. Finally, we determined the downstream target of miR-190-5p by Targetscan system and dual luciferase reporter assay. Results The expression of miR-190-5p in an I/R rat myocardium was significantly lower than that in normal rats. After treatment of I/R rats with agomir miR-190-5p, the ischemic area of rat myocardium and the concentration of LDH decreased. The results of echocardiography and HE staining also found that overexpression of miR-190-5p improved the structure and function of rat myocardium. miR-190-5p was also found to improve the viability of H9c2 cells in vitro and reduce the level of apoptosis of H9c2 cells. The results of Targetscan system and dual luciferase reporter assay found that miR-190-5p targeted to inhibit pleckstrin homology domain leucine-rich repeat protein phosphatase 1 (PHLPP1). In addition, inhibition of PHLPP1 was found to improve the viability of H9c2 cells. Conclusion Therefore, miR-190-5p can reduce the inflammation and apoptosis of myocardium by targeting PHLPP1, thereby alleviating MIRI.

Short-Chain Fatty Acids Reduced Renal Calcium Oxalate Stones by Regulating the Expression of Intestinal Oxalate Transporter SLC26A6.

ABSTRACTRenal calcium oxalate (CaOx) stone is a common urologic disease with a high prevalence and recurrence rate. However, short-chain fatty acids (SCFAs) are less often reported in the prevention of urolithiasis. This study aimed to explore the effect of SCFAs on the renal CaOx stone formation and the underlying mechanisms. Ethylene glycol was used to induce renal CaOx crystals in rats. SCFAs (acetate, propionate, or butyrate) were added as supplements to the drinking water with or without antibiotics. Because intestinal oxalate transporters SLC26A6 and SLC26A3 regulate the excretion and absorption of oxalate in the intestine, we injected adeno-associated virus 9 (AAV9)-SLC26A6-shRNA (short hairpin RNA) and AAV9-SLC26A3 into the tail vein of rats to suppress SLC26A6 and overexpress SLC26A3 expression in the intestine, respectively, to explore the role of SLC26A3 and SLC26A6 (SLC26A3/6) in the reduction of renal CaOx crystals induced by SCFAs. Results showed that SCFAs reduced renal CaOx crystals and urinary oxalate levels but, however, increased the abundance of SCFA-producing bacteria and cecum SCFA levels. SCFA supplements still reduced renal crystals and urinary oxalate after gut microbiota depletion. Propionate and butyrate downregulated intestinal oxalate transporter SLC26A3 expression, while acetate and propionate upregulated SLC26A6 expression, both in vivo and in vitro. AAV9-SLC26A3 exerted a protective effect against renal crystals, while AAV9-SLC26A6-shRNA contributed to the renal crystal formation even though the SCFAs were supplemented. In conclusion, SCFAs could reduce urinary oxalate and renal CaOx stones through the oxalate transporter SLC26A6 in the intestine. SCFAs may be new supplements for preventing the formation of renal CaOx stones.IMPORTANCE Some studies found that the relative abundances of short-chain-fatty-acid (SCFA)-producing bacteria were lower in the gut microbiota of renal stone patients than healthy controls. Our previous study demonstrated that SCFAs could reduce the formation of renal calcium oxalate (CaOx) stones, but the mechanism is still unknown. In this study, we found that SCFAs (acetate, propionate, and butyrate) reduced the formation of renal calcium oxalate (CaOx) crystals and the level of urinary oxalate. Depleting gut microbiota increased the amount of renal crystals in model rats, and SCFA supplements reduced renal crystals and urinary oxalate after gut microbiota depletion. Intestinal oxalate transporter SLC26A6 was a direct target of SCFAs. Our findings suggested that SCFAs could reduce urinary oxalate and renal CaOx stones through the oxalate transporter SLC26A6 in the intestine. SCFAs may be new supplements for preventing the formation of renal CaOx stones.

Mesenchymal stem cells moderate experimental autoimmune uveitis by dynamic regulating Th17 and Breg cells response.

Mesenchymal stem cells (MSCs) are adult stem cells from mesoderm with multi potential differentiation, and are being widely studied as a promising treatment for autoimmune diseases. The main inflammatory factors of experimental autoimmune uveitis (EAU) are T helper type 1 (Th1) and Th17. Regulatory B cells (Bregs) are a newly designated B cell subgroup, which has been proved to play a key role in regulating inflammation, autoimmunity and cancer. In this regard, we establish the EAU model by injecting interphotoreceptor retinoid-binding protein combined with complete Freund's adjuvant into the tail vein and bilateral thighs of rats, and inject MSCs or equal volume of phosphate buffer saline intraperitoneally on the day of immunization. Dynamic changes of cell subsets and cytokine expression are tested at different time periods to explore the relationship between MSCs treatment and disease prognosis during EAU course. Our results suggest that compared with the model control group, MSCs treatment can significantly reduce the production of Th1 and Th17 cytokines during EAU, while the production of regulatory B cells (Bregs) cytokines is significantly increased. At the same time, MSCs can reduce the proportion of Th17 in lymphocytes while the proportion of Bregs is elevated, thus inhibiting the differentiation and activity of interleukin in EAU rats. All this results provide more powerful evidence for cell therapy of autoimmune uveitis.

Different Anesthetic Drugs Mediate Changes in Neuroplasticity During Cognitive Impairment in Sleep-Deprived Rats via Different Factors.

BackgroundPerioperative neuro-cognitive disorders (PND) are preoperative and postoperative complications of multiple nervous systems, typically manifested as decreased memory and learning ability after surgery. It was used to replace the original definition of postoperative cognitive dysfunctions (POCD) from 2018. Our previous studies have shown that sevoflurane inhalation can lead to cognitive dysfunction in Sprague-Dawley rats, but the specific mechanism is still unclear.Material/MethodsThirty-six male Sprague-Dawley rats were randomly divided into 6 groups (n=6): the SD group was given 24-h acute sleep deprivation; Sevoflurane was inhaled for 2 h in the Sevo group. Two mL propofol was injected into the tail vein of rats in the Prop group. The rats in the SD+Sevo group and SD+Prop group were deprived of sleep before intervention in the same way as before.ResultsWe noted significant behavioral changes in rats treated with SIK3 inhibitors or tau phosphorylation agonists before propofol injection or sevoflurane inhalation, with associated protein levels and dendritic spine density documented. Sevoflurane anesthesia-induced cognitive impairment following acute sleep deprivation was more pronounced than sleep deprivation-induced cognitive impairment alone and resulted in increased brain SIK3 levels, increased phosphorylation of total tau and tau, and decreased acetylation modifications. After using propofol, the cognitive function returned to baseline levels with a series of reversals of cognitive dysfunction.ConclusionsThese results suggest that sevoflurane inhalation via the SIK3 pathway aggravates cognitive impairment after acute sleep deprivation and that propofol anesthesia reverses the effects of sleep deprivation by affecting modifications of tau protein.

Proteomic study on the damage of learning and memory ability of rat offspring caused by chronic stress during pregnancy

Objective: To study the differential protein and signal pathway related to the impairment of learning and memory ability of offspring caused by chronic stress during pregnancy and explore the possible mechanism. Methods: From July to October 2019, sixteen SPF free female SD rats aged 80-90 days, weighing (200±20) g. Twelve SPF grade male SD rats aged 90-100 days, weighing (220±20) g. After a week of adaptive feeding, the female rats were randomly divided into control group and model group (8 rats in each group) , male rats were divided into control mating group (n=8) and model mating group (n=4) . Chronic unpredictable mild stress (CUMS) model was established and stimulated continuously for 21 days. One day before stress, the first, seventh, fourteenth and 21th day after stress, the blood was collected from the inner canthus vein of the female rats, and the content of corticosterone was determined. Morris water maze test was used to detect the spatial learning and memory ability of offspring rats. The morphological changes of hippocampus were observed by HE and Nissl staining. The proteomic correlation analysis of offspring rats' hippocampus was performed by isobaric tags for relative and absolute quantification (iTRAQ) technique. Results: Compared with the control group, the content of plasma corticosterone in the model group was significantly higher (F=7.717, P<0.05) , and the model was successfully established. In Morris water maze test, compared with the control offspring group, the escape latency was longer, the average swimming speed was lower, the number of crossing platform was less, and the target quadrant run was shorter in the model offspring group (P<0.05) . The pathological results showed that the morphology of cells in the hippocampal tissue of the model offspring group was irregular, the number of neurons was small, Nissl body was unevenly distributed, the volume was small and the number was small. Mass spectrometry analysis showed that a total of 5065 proteins were screened out in the two offspring groups, and 26 proteins were differentially expressed (P<0.05) , of which 19 proteins were up-regulated and 7 proteins were down regulated. The differential proteins were mainly involved in 23 biological processes, 14 cellular components and 9 molecular functions. Kyoto Encyclopedia of genes and genomes (KEGG) enrichment analysis showed that 57 pathways were enriched, of which 8 signaling pathways were significantly enriched (P<0.05) . There were 5 signaling pathways that might be involved in the impairment of learning and memory ability of offspring, including neuroactive ligand receptor interaction, cGMP-PKG signaling pathway, adhesion and connection, adhesion and connection FoxO signaling pathway and Notch signaling pathway, mainly including tyrosine protein kinase receptor, tyrosine kinase receptor and Notch signaling pathway, and α2A adrenergic receptor, cGMP dependent protein kinase and other differential proteins may be involved in the injury process. Conclusion: The damage of learning and memory ability of offspring may be caused by chronic stress during pregnancy rats. The enriched signal pathway and key differential proteins of proteomics may play an important role in the process of damage.

Occluded Superior Mesenteric Artery and Vein. Therapy with the Stable Gastric Pentadecapeptide BPC 157.

Background. We investigated the occluded essential vessel tributaries, both arterial and venous, occluded superior mesenteric vein and artery in rats, consequent noxious syndrome, peripherally and centrally. As therapy, we hypothesized the rapidly activated alternative bypassing pathways, arterial and venous, and the stable gastric pentadecapeptide BPC 157 since it rapidly alleviated venous occlusion syndromes. Methods. Assessments were performed for 30 min (gross recording, venography, ECG, pressure, microscopy, biochemistry, and oxidative stress), including portal hypertension, caval hypertension, aortal hypotension, and centrally, the superior sagittal sinus hypertension; systemic arterial and venous thrombosis, ECG disturbances, MDA-tissue increase, the multiple organs lesions, heart, lung, liver, kidney and gastrointestinal tract, including brain (swelling, and cortex (cerebral, cerebellar), hypothalamus/thalamus, hippocampus lesions). Rats received BPC 157 medication (10 µg/kg, 10 ng/kg) intraperitoneally at 1 min ligation-time. Results. BPC 157 rapidly activated collateral pathways. These collateral loops were the superior mesenteric vein-inferior anterior pancreaticoduodenal vein-superior anterior pancreaticoduodenal vein-pyloric vein-portal vein pathway, an alternative pathway toward inferior caval vein via the united middle colic vein and inferior mesenteric vein through the left colic vein, and the inferior anterior pancreaticoduodenal artery and inferior mesenteric artery. Consequently, BPC 157 counteracted the superior sagittal sinus, portal and caval hypertension, aortal hypotension, progressing venous and arterial thrombosis peripherally and centrally, ECG disturbances attenuated. Markedly, the multiple organs lesions, heart, lung, liver, kidney, and gastrointestinal tract, in particular, as well as brain lesions, and oxidative stress in tissues were attenuated. Conclusions. BPC 157 therapy rapidly recovered rats, which have complete occlusion of the superior mesenteric vein and artery.

Ultrafast Self‐Gelling and Wet Adhesive Powder for Acute Hemostasis and Wound Healing

AbstractAchieving rapid and effective hemostasis on irregularly shaped, non‐compressible visceral, and high‐pressure arterial bleeding wounds remains a critical clinical challenge. Herein, an ultrafast self‐gelling and wet adhesive polyethyleneimine/polyacrylic acid/quaternized chitosan (PEI/PAA/QCS) powder is reported as the hemostatic material and wound dressing. PEI/PAA/QCS powder deposited on bleeding wounds can rapidly absorb a large amount of blood to concentrate coagulation factors. Meanwhile, the powder can form an adhesive hydrogel in situ within 4 s upon hydration to form a pressure‐resistant physical barrier. Furthermore, PEI/PAA/QCS hydrogels can aggregate blood cells and platelets to enhance hemostasis. Depositing PEI/PAA/QCS powder on various bleeding wounds, including at the liver and heart, high‐pressure femoral artery and tail vein of rats, arrests the bleeding around 10 s with no rebleeding after ten minutes. Excellent hemostasis of PEI/PAA/QCS powder is further demonstrated against massive hemorrhage in porcine spleen and liver in vivo, which are non‐compressible organs with abundant blood supply. In addition, the powder can be used as a wound dressing to promote the healing of the full‐thickness skin wounds. The advantages of PEI/PAA/QCS powder including rapid and effective hemostasis, effective wound healing, easy usage, low cost, and adaptability to fit complex target sites make it a promising biomaterial for surgical applications.

SiRNA in MSC-derived exosomes silences CTGF gene for locomotor recovery in spinal cord injury rats

BackgroundHow to obtain a small interfering RNA (siRNA) vector has become a moot point in recent years. Exosomes (Exo) show advantages of long survival time in vivo, high transmission efficiency, and easy penetration across the blood-spinal cord barrier, renowned as excellent carriers of bioactive substances.MethodsWe applied mesenchymal stem cell (MSC)-derived exosomes as the delivery of synthesized siRNA, which were extracted from rat bone marrow. We constructed exosomes-siRNA (Exo-siRNA) that could specifically silence CTGF gene in the injury sites by electroporation. During the administration, we injected Exo-siRNA into the tail vein of SCI rats,ResultsIn vivo and in vitro experiments showed that Exo-siRNA not only effectively inhibited the expressions of CTGF gene, but quenched inflammation, and thwarted neuronal apoptosis and reactive astrocytes and glial scar formation. Besides, it significantly upregulated several neurotrophic factors and anti-inflammatory factors, acting as a facilitator of locomotor recovery of rats with spinal cord injury (SCI).ConclusionsIn conclusion, this study has combined the thoroughness of gene therapy and the excellent drug-loading characteristics of Exo for the precise treatment of SCI, which will shed new light on the drug-loading field of Exo.

Circulating NGF is correlated with indexes of diabetes progression and P2X 3 expression in UCD‐T2DM rats

Type 2 diabetes is associated with neuropathic symptoms, including development of peripheral neuropathy and an exaggerated exercise pressor reflex, both of which have been demonstrated in UC Davis Type 2 diabetes mellitus (UCD-T2DM) rats. This novel animal model more closely mimics the human disease state than traditional T2DM rodent models. Several studies have demonstrated changes in nerve growth factor (NGF) in diabetic patients, with some showing increases and others decreases, and this has been proposed as a potential driver of the development of peripheral neuropathy. Additionally, increased expression of purinergic 2X3 (P2X3) receptors has been suggested as a potential mechanism underlying peripheral nerve sensitization. However, interactions between these factors during diabetes progression are not fully understood. Therefore, the objective of this study was to investigate the relations between NGF, P2X3, and peripheral neuropathy during diabetes progression in UCD-T2DM rats. We hypothesized that NGF levels would be correlated with traditional indexes of diabetes (glucose and HbA1c) as well as P2X3 expression and mechanical allodynia as measured by paw withdrawal threshold. Methods Blood was collected monthly from the tail vein of male UCD-T2DM rats from 4 to 8 months of age. Serum levels of NGF, leptin, and insulin were measured by ELISA. Development of mechanical allodynia was tracked monthly using Von Frey filaments to measure paw withdrawal threshold. At 8 months of age, L4-5 dorsal root ganglia were harvested and P2X3 receptor protein levels were quantified using the Jess automated western blotting platform. Pearson correlations were calculated using Graphpad Prism 9. Results Consistent with wasting and loss of pancreatic beta cell function during diabetes progression, glucose and HbA1c increased significantly over time whereas body weight, insulin, and leptin levels decreased. Circulating NGF concentration was negatively correlated with glucose (r=-0.61, P<0.01) and HbA1c (r=-0.79, p<0.01) demonstrating that NGF decreased with the progression of diabetes. Circulating NGF concentration was positively correlated with body weight (r=0.61, p<0.01), insulin (r=0.77, p<0.01), and leptin (r=0.82, p<0.01) thereby showing the same decreasing trend with diabetes progression. Interestingly, NGF was negatively correlated with P2X3 receptor expression (r=-0.81, p=0.03) and neither NGF nor P2X3 were significantly associated with mechanical allodynia (NGF: r=0.14, p=0.45; P2X3: r= 0.15, p=0.75). Conclusion Circulating NGF is significantly associated with several indexes of diabetes progression in UCD-T2DM rats, including glucose, HbA1c, leptin, and insulin levels. Though decreasing concentrations of NGF are associated with increases in P2X3 receptor protein expression, neither NGF nor P2X3 appear to be associated with the development of mechanical allodynia.

A New Stable Isotope Method for Quantifying Potassium Distribution and Fluxes In Vivo

The potassium (K+) gradient across a cell membrane is a critical determinant of membrane potential. Thus, disturbances in K+ homeostasis, which involve both renal and extrarenal mechanisms, can provoke life-threatening cardiovascular events. We know that K+ traverses membranes through channels, co-transporters, and ATPases, but determining mechanisms controlling fluxes between extracellular and intracellular compartments in vivo is hampered by a lack of appropriate methods to quantify K+ fluxes in vivo, particularly those into and out of cells. Objective and Hypothesis: The objective of this study was to implement stable K+ isotopes to quantify K+ fluxes in vivo. 41K and 39K are stable isotopes of K+ with 39K roughly 14-fold more abundant than 41K. We tested the hypothesis that the 41K/39K ratio in rat plasma in vivo is altered by intravenous 41K infusion, and that these changes can be analyzed to quantify K+ distribution and fluxes. Methods: 41K (as KCl) was infused (0.5 mg 41K / h) for 1 h into tail vein of male Wistar rats (~300 g body weight; n = 4), and blood was sampled from tail artery before, during, and after the 41K infusion. Plasma was obtained by centrifugation, and 41K/39K ratio measured using inductively coupled plasma mass spectrometry. Results: The plasma 41K/39K ratio increased during the 1-h 41K infusion and decreased upon cessation of the infusion (Figure 1; data expressed as change from the baseline, d41K/39K) whereas the concentration of total K+ in plasma (i.e., 41K + 39K) was not significantly increased by the 41K infusion (data not shown). The time course of d41K/39K was analyzed using a 2-compartmental (2-C) model of K+ distribution and elimination, including the extracellular (ECF, compartment 1) and the intracellular (ICF, compartment 2) fluid K+ pools, K+ fluxes between the pools, and renal K+ excretion (Figure 2). We assume ECF is instantly equilibrated with plasma. The model fit the data (Figure 1), and model parameters were robustly identified (V1 [volume of ECF] = 29.6 ± 3.6 ml; k01 = 0.012 ± 0.003 min-1; k21 = 0.13 ± 0.02 min-1; and k12 = 0.012 ± 0.001 min-1). Conclusions: This novel approach using stable isotopes can quantify K+ distribution and fluxes in vivo and can be implemented to identify mechanisms in (patho)physiological regulation of potassium homeostasis.

Exercise training rescues the electrical activity of liver-projecting DMNV neurones in response to oxytocin in spontaneously hypertensive rats.

A neural circuit between the paraventricular nucleus of the hypothalamus (PVN) and the dorsal motor nucleus of the vagus (DMNV) constitutes part of an important parasympathetic autonomic pathway that controls hepatic glucose production. Intracerebroventricular injection of insulin activates oxytocinergic neurones in the PVN and elicits the release of oxytocin into the circulation, which plays an important role in the metabolism of glucose. Moreover, the central action of insulin can reduce the concentration of glucose in blood taken from the hepatic vein of Wistar rats via activation of vagal efferent nerves to the liver. This mechanism is impaired in sedentary spontaneously hypertensive rats (SHR). Because aerobic exercise increases vagal tone, partly mediated by increasing the oxytocinergic connections between the PVN and DMNV, we hypothesised that oxytocin (OT) might alter the excitability of liver-projecting DMNV neurones. Thus, we investigated the effects of OT on electrical properties of the liver-projecting DMNV neurones from Wistar, SHR subjected to 4weeks of exercise training, as well sedentary controls, using whole cell patch-clamping. The results show that OT increased the resting membrane potential of DMNV neurones in Wistar rats, as well as the firing frequency of these cells, but not in sedentary SHR. However, in SHR subjected to 4weeks of exercise training, the effects of OT on liver-projecting DMNV neurones of were similar to those seen in Wistar rats. These findings show that OT elicits similar changes in the electrophysiological properties of liver-projecting DMNV neurones of Wistar and exercise-trained but not sedentary SHR. These results indicate that exercise training can restore the sensitivity of liver-projecting DMNV neurones of exercise-trained SHR to OT.

Effects of normobaric hyperoxia intervention on renal ischemia-reperfusion injury in rats

Objective: To investigate the effects of normobaric hyperoxia intervention on renal ischemia-reperfusion injury in rats and its possible mechanism. Methods: Twenty-one adult male SD rats were enrolled and their right kidneys were excised. After two weeks, they were randomly assigned to 3 groups, with 7 rats in each group, namely sham-operated group (Group S), ischemia-reperfusion group (Group I/R), and normobaric hyperoxia+ischemia-reperfusion group (Group NBHO+I/R). In group S, only the left renal pedicle was isolated, but no ischemic treatment was performed. However, in group I/R and group NBHO+I/R, left renal pedicles were separated and left renal ischemia was induced by noninvasive arterial clamp for 45 min, and after 24 h of reperfusion, rats in group S and group I/R inhaled regular concentration of oxygen (21%), while rats in group NBHO+I/R inhaled high concentration of oxygen (60%), 2 h at each time, once a day for 7 days. On the 7th day after surgery, blood urea nitrogen (BUN) and creatinine (Cr) levels were measured by taking blood from the orbital veins of rats. The content of malondialdehyde (MDA) and superoxide dismutase (SOD) was detected from the left kidney tissues. The mRNA and protein contents of Keap1 and Nrf2 gene in kidney tissues were determined by qPCR and Western Blotting, respectively. Hematoxylin-eosin staining (HE) was employed to observe the pathological changes of kidney tissue. Immunohistochemical staining was used to measure the protein expression of Keap1 and Nrf2 in kidney tissues. Results: Compared with group S, the serum BUN [(10.7±1.7) mmol/L, (8.4±1.0) mmol/L vs (6.1±1.3) mmol/L, both P<0.05] and Cr [(81.0±3.7) μmol/L, (62.9±3.4) μmol/L vs (48.3±2.9) μmol/L, both P<0.05] levels of rats in the group I/R and group NBHO+I/R increased, and the I/R group had the most significant increase. Compared with group S, the MDA content of kidney tissue in the rats of group I/R and NBHO+I/R increased [(10.5±1.0) μmol/L, (8.6±0.8) μmol/L vs (6.5±0.5) μmol/L, both P<0.05], but the MDA content in group NBHO+I/R was lower than that of group I/R (P<0.05). Compared with group S, the SOD content in the kidney tissues of rats in both group I/R and group NBHO+I/R decreased. However, the SOD content of group NBHO+I/R was higher than that of group I/R (P<0.05). Compared with group S, the mRNA and protein contents of Keap1 gene in kidney tissues of group I/R and group NBHO+I/R decreased, and group NBHO+I/R had the most significant decrease (P<0.05). However, compared with group S, mRNA and protein expressions of Nrf2 gene increased in kidney tissues of group I/R and group NBHO+I/R, and NBHO+I/R group had the most significant increase (P<0.05). Postoperative pathological results suggested that compared with group S, the pathological damage of kidney tissues in group I/R and group NBHO+I/R increased, but the degree of damage in group NBHO+I/R was lower than that in group I/R. Conclusion: Normobaric hyperoxia intervention may have protective effects on renal ischemia-reperfusion injury in rats by activating Keap1-Nrf2 signaling pathway.