Male Sprague-Dawley Rat Model Research Articles

A neutrophil elastase inhibitor, sivelestat, attenuates sepsis-induced acute kidney injury by inhibiting oxidative stress

BackgroundSivelestat, a selective inhibitor of neutrophil elastase (NE), can mitigate sepsis-related acute lung injury. However, the role of sivelestat in inhibiting oxidative stress and attenuating sepsis-related acute kidney injury (AKI) remains unclear. Here, we reported the effects of sivelestat against oxidative stress-induced AKI by suppressing the production of oxidative stress indicators. Materials and methodsA male Sprague-Dawley rat model of sepsis was established by cecal ligation and puncture (CLP). Sivelestat or normal saline was administered into jugular vein with a sustained-release drug delivery system. Indicators of inflammation and AKI, including white blood cells (WBC), neutrophils, lymphocytes, C-reactive proteins (CRP), procalcitonin (PCT), blood urea nitrogen (BUN), creatinine (Cr) and uric acid (UA), were assessed at 24 h post-sivelestat treatment. Indicators of liver injury, including direct bilirubin (DBIL), indirect bilirubin (IBIL), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), were also assessed at 24 h post-sivelestat treatment. Indicators of oxidative stress, including superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px), were assessed at 12 h and 24 h post-sivelestat treatment. At 24 h post-sivelestat treatment, H&E staining of kidney and liver tissue was performed to observe pathological alterations. ResultsAt 24 h post normal saline or sivelestat (0.2 g/kg body weight) treatment, WBC, neutrophil, CRP, PCT, MDA, BUN, Cr, UA, AST, ALT, DBIL and IBIL were increased, while SOD and GSH-Px were decreased, in septic rats treated with normal saline compared with that in non-septic rats treated with normal saline (all p < 0.05). The changes of these indicators were reversed in septic rats treated with sivelestat compared with that in septic rats treated with normal saline (all p < 0.05). Similar results were found regarding the levels of oxidative stress indicators at 12 h post-sivelestat treatment. The degenerative histopathological changes in both kidney and liver tissues were ameliorated upon sivelestat treatment. ConclusionsSivelestat plays a protective role in sepsis-related AKI by inhibiting oxidative stress. Our study reveals a possible therapeutic potential of sivelestat for oxidative stress-induced AKI.

Isoproterenol pre-treatment improve the therapeutic efficacy of cardiosphere-derived cells transplantation for myocardial infarction.

This study aimed to investigate the effect of isoproterenol pre-treatment on the therapeutic efficacy of cardiosphere-derived cells (CDCs) transplantation for myocardial infarction (MI). Thirty 8-week-old male Sprague-Dawley (SD) rat model of MI was generated by ligation of the left anterior descending artery. The MI rats were treated with PBS (MI group, n=8), CDCs (MI + CDC group, n=8) and isoproterenol pre-treated CDCs (MI + ISO-CDC group, n=8), respectively. In the MI + ISO-CDC group, CDCs were pre-treated by 10-6 M isoproterenol and the cultured for additional 72 h, then injected to the myocardial infraction area like other groups. At 3 weeks after the operation, echocardiographic, hemodynamic, histological assessments and Western blot were performed to compare the CDCs differentiation degree and therapeutic effect. Isoproterenol treatment (10-6 M) simultaneously inhibited proliferation and induced apoptosis of CDCs, up-regulated proteins of vimentin, cTnT, α-sarcomeric actin and connexin 43, and down-regulated c-Kit proteins (all P<0.05). The echocardiographic and hemodynamic analysis demonstrated that the MI rats in the two CDCs transplantation groups had significantly better recovery of cardiac function than the MI group (all P<0.05). MI + ISO-CDC group had better recovery of cardiac function than the MI + CDC group, although the differences did not reach significant. Immunofluorescence staining showed that the MI + ISO-CDC group had more EdU-positive (proliferating) cells and cardiomyocytes in the infarct area than the MI + CDC group. MI + ISO-CDC group had significantly higher protein levels of c-Kit, CD31, cTnT, α-sarcomeric actin and α-SMA in the infarct area than the MI + CDC group. These results suggested that in CDCs transplantation, isoproterenol pre-treated CDCs can provide a better protective effect against MI than the untreated CDCs.

GLP-1R knockdown abrogates the protective effects of liraglutide on ischaemic stroke via inhibition of M2 polarisation and activation of NLRP3 inflammasome by reducing Nrf2 activation

Liraglutide has been recently discovered to penetrate the blood–brain barrier to exert neuroprotective effects. However, relevant mechanisms of the protective effects of liraglutide on ischaemic stroke remain to be elucidated. This study examined the mechanism of GLP-1R in regulating the protective effect of liraglutide against ischaemic stroke. Middle cerebral artery occlusion (MCAO) male Sprague-Dawley rat model with/without GLP-1R or Nrf2 knockdown was established and subjected to liraglutide treatment. Then neurological deficit and brain oedema of rats was evaluated and brain tissues were subjected to TTC, Nissl, TUNEL and immunofluorescence staining. Rat primary microglial cells firstly underwent lipopolysaccharide (LPS) treatment, then GLP-1R or Nrf2 knockdown treatment, and finally Liraglutide treatment to research the NLRP3 activation. As a result, Liraglutide protected rats' brain tissues after MCAO, which attenuated brain oedema, infarct volume, neurological deficit score, neuronal apoptosis and Iba1 expression but enhanced live neurons. However, GLP-1R knockdown abrogated these protective effects of liraglutide on MCAO rats. According to in vitro experiments, Liraglutide promoted M2 polarisation, activated Nrf2 and inhibited NLRP3 activation in LPS-induced microglial cells, but GLP-1R or Nrf2 knockdown reversed these effects of Liraglutide on LPS-induced microglial cells. Further, Nrf2 knockdown counteracted the protection of liraglutide on MCAO rats, whereas sulforaphane (agonist of Nrf2) counteracted the effect of Nrf2 knockdown on liraglutide-treated MCAO rats. Collectively, GLP-1R knockdown abrogated the protection of liraglutide on MCAO rats by activating NLRP3 via inactivating Nrf2.

Bioinformatics prediction and experimental verification of a novel microRNA for myocardial fibrosis after myocardial infarction in rats.

MicroRNAs (miRNAs) are endogenous noncoding single-stranded small RNAs. Numerous studies have shown that miRNAs have pivotal roles in the occurrence and development of myocardial fibrosis (MF). However, miRNA expression profile in rats with MF after myocardial infarction (MI) is not well understood. The present study aimed to find the potential miRNA for MF post MI. SPF male Sprague-Dawley (SD) rat models of acute myocardial infarction (AMI) were established by ligating the anterior descending branch of the left coronary artery, while sham-operated rats were only threaded without ligation as a control group. Hematoxylin-eosin and Masson trichrome staining were used to detect myocardial histopathological changes for model evaluation. The differentially expressed miRNAs were detected by using the Agilent Rat miRNA gene chip in the myocardial tissue of the infarct marginal zone. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed by DAVID. The expression of miR-199a-5p was verified by real-time fluorescence quantitative PCR (qRT-PCR). Transfected miR-199a-5p mimics into cardiac fibroblasts (CFs) to construct cell models of miR-199a-5p overexpression. Dual-luciferase reporter assay was employed to validate the target gene of miR-199a-5p. The protein expression of the target gene in CFs transfected with miR-199a-5p mimics were detected by Western blot. Myocardial fibrosis was exacerbated in the model group compared with the control group. Thirteen differentially expressed miRNAs between the two groups were screened and their expression levels in the model group were all higher than those in the control group. The expression of miR-199a-5p was significantly increased in the model group in qRT-PCR, which was consistent with the results of the gene chip. KEGG enrichment analysis showed that the target genes of miR-199a-5p were enriched in the insulin signaling pathway. Furthermore, dual-luciferase reporter assay indicated that miR-199a-5p could negatively regulate the expression of GSK-3β. After transfection, the expression of miR-199a-5p was increased in the miR-199a-5p mimics group. The protein expression of GSK-3β was decreased in CFs transfected with miR-199a-5p mimics. Our study identified miR-199a-5p could promote the progression of myocardial fibrosis after myocardial infarction by targeting GSK-3β, which provides novel targets for diagnosis and treatment of MF.

Effect of Bacillus subtilis, Enterococcus faecium, and Enterococcus faecalis supernatants on serotonin transporter expression in cells and tissues.

BACKGROUND Bacillus subtilis (B. subtilis), Enterococcus faecium (E. faecium), and Enterococcus faecalis (E. faecalis) are probiotics that are widely used in the clinical treatment of irritable bowel syndrome (IBS). Whether the supernatants of these three probiotics can improve gastrointestinal sensation and movement by regulating the serotonin transporter (SERT) expression needs to be clarified.AIMTo investigate whether B. subtilis, E. faecium, and E. faecalis supernatants can upregulate SERT expression in vitro and in vivo. METHODSCaco-2 and HT-29 cells were stimulated with probiotic culture supernatants for 12 and 24 h, respectively. A male Sprague-Dawley rat model of post-infectious irritable bowel syndrome (PI-IBS) was established and the rats were treated with phosphate-buffered saline (group A) and three probiotics culture supernatants (groups B, C, and D) for 4 wk. The levels of SERT were detected by quantitative PCR and western blotting. RESULTSThe levels of SERT at post-treatment 12 and 24 h were significantly elevated in Caco-2 cells treated with B. subtilis supernatant compared with those in the control group (aP < 0.05). Those levels were markedly upregulated in Caco-2 cells stimulated with E. faecium and E. faecalis supernatants at 24 h (aP < 0.05). In addition, SERT expression in groups B, C, and D was significantly higher than that in group A in the 2nd wk (aP < 0.05). Increased SERT expression was only found in group D in the 3rd wk (aP < 0.05). However, there was no significant difference in SERT expression between the groups in the last week (P > 0.05).CONCLUSIONThe supernatants of B. subtilis, E. faecium, and E. faecalis can upregulate SERT expression in intestinal epithelial cells and the intestinal tissues in the rat model of PI-IBS.

Exogenous ketone ester delays CNS oxygen toxicity without impairing cognitive and motor performance in male Sprague-Dawley rats.

Hyperbaric oxygen (HBO2) is breathing >1 atmosphere absolute (ATA; 101.3 kPa) O2 and is used in HBO2 therapy and undersea medicine. What limits the use of HBO2 is the risk of developing central nervous system (CNS) oxygen toxicity (CNS-OT). A promising therapy for delaying CNS-OT is ketone metabolic therapy either through diet or exogenous ketone ester (KE) supplement. Previous studies indicate that KE induces ketosis and delays the onset of CNS-OT; however, the effects of exogeneous KE on cognition and performance are understudied. Accordingly, we tested the hypothesis that oral gavage with 7.5 g/kg induces ketosis and increases the latency time to seizure (LSz) without impairing cognition and performance. A single oral dose of 7.5 g/kg KE increases systemic β-hydroxybutyrate (BHB) levels within 0.5 h and remains elevated for 4 h. Male rats were separated into three groups: control (no gavage), water-gavage, or KE-gavage, and were subjected to behavioral testing while breathing 1 ATA (101.3 kPa) of air. Testing included the following: DigiGait (DG), light/dark (LD), open field (OF), and novel object recognition (NOR). There were no adverse effects of KE on gait or motor performance (DG), cognition (NOR), and anxiety (LD, OF). In fact, KE had an anxiolytic effect (OF, LD). The LSz during exposure to 5 ATA (506.6 kPa) O2 (≤90 min) increased 307% in KE-treated rats compared with control rats. In addition, KE prevented seizures in some animals. We conclude that 7.5 g/kg is an optimal dose of KE in the male Sprague-Dawley rat model of CNS-OT.

In vivo Toxicity Assessment of Refined Red Palm-pressed Mesocarp Olein in Sprague-Dawley Rats.

Refined red palm-pressed mesocarp olein (PPMO) is recovered from palm-pressed mesocarp fiber, which is a by-product from palm oil mill. Its utilization in food industry is extremely limited even though it contains various phytonutrients. Thus, this study aimed to evaluate its toxicity effects by using the male Sprague-Dawley rat model. The rats were administered with a single dose of 2 g/kg PPMO in an acute toxicity study while administered with 2, 1, or 0.5 g/kg PPMO daily for 28 days in a sub-chronic toxicity study. The mortality, oral LD50 value, clinical observation, body and organ weight, hematological and biochemical analyses, pathological and histopathological examinations were assessed. The overall outcomes indicated that PPMO is non-toxic up to 2 g/kg and considered safe to be used in food application, especially as functional food ingredient and supplement attributed to its phytonutrients. Besides, this study provides an insight in alternative utilization of the wastes from palm oil mill.

Inhibition of nitric oxide synthase aggravates brain injury in diabetic rats with traumatic brain injury.

Studies have shown that hyperglycemia aggravates brain damage by affecting vascular endothelial function. However, the precise mechanism remains unclear. Male Sprague-Dawley rat models of diabetes were established by a high-fat diet combined with an intraperitoneal injection of streptozotocin. Rat models of traumatic brain injury were established using the fluid percussion method. Compared with traumatic brain injury rats without diabetic, diabetic rats with traumatic brain injury exhibited more severe brain injury, manifested as increased brain water content and blood-brain barrier permeability, the upregulation of heme oxygenase-1, myeloperoxidase, and Bax, the downregulation of occludin, zona-occludens 1, and Bcl-2 in the penumbra, and reduced modified neurological severity scores. The intraperitoneal injection of a nitric oxide synthase inhibitor N(5)-(1-iminoethyl)-L-ornithine (10 mg/kg) 15 minutes before brain injury aggravated the injury. These findings suggested that nitric oxide synthase plays an important role in the maintenance of cerebral microcirculation, including anti-inflammatory, anti-oxidative stress, and anti-apoptotic activities in diabetic rats with traumatic brain injury. The experimental protocols were approved by the Institutional Animal Care Committee of Harbin Medical University, China (approval No. ky2017-126) on March 6, 2017.

Influence of lithium treatment on pathological changes: an investigation on male Sprague–Dawley rat model

Mood disorder is a major disarray of the nervous system that affects the cognition and memory functions of the brain. Among many drugs and agents, lithium is widely used to manage mood disorder. In this study, lithium carbonate fed to male Sprague–Dawley rats and their toxic effects associated with their different organs (Brain, Kidney, Heart, Liver and Spleen) were studied. Forty-eight male Sprague–Dawley rats were used for the experiments, and 24 rats among them were fed with lithium carbonate (2 g/kg of body weight) for 6 weeks. The morphological and histopathological changes corresponding to lithium were evaluated by light microscopy in brain, kidney, liver, spleen and heart and by electron microscopy in brain. Administration of lithium carbonate along with rat chow did register therapeutic lithium levels, and changes in the brain lithium levels were also observed. Our results illustrated drastic changes in structures, size and shape of the brain, coupled with condensed nucleus, and swollen mitochondria and detached rough endoplasmic reticulum in lithium-fed rats were observed by transmission electron microscopy. The heart of lithium-fed rats showed separation of myocardial fibers. Brain, heart, kidney, liver and spleen showed increase in weight. Hepatocytes, sinusoidal congestions, changes in eosinophil granules in cytoplasm and lesser vacuolation were observed in lithium-fed rats. The explicit understanding of the lithium’s effects on the structural, morphological and cellular changes in rats can be a promising supplementary therapeutic strategy to subdue lithium’s toxicity effect on mood disorder patients under treatment of lithium. Based on the investigations carried out in this study, at a dosage of 2 g/kg body weight, lithium caused increase in anxiety-like behavior. This further led to neurobehavioral conditions and decreased locomotor activity. This study thus suggests that the effective dosage/delivery of lithium is critical in its usage as an anti-depressive agent.

Reg3α and Reg3β Expressions Followed by JAK2/STAT3 Activation Play a Pivotal Role in the Acceleration of Liver Hypertrophy in a Rat ALPPS Model.

To explore the underlying mechanism of rapid liver hypertrophy by liver partition in associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), liver partition at different sites was investigated. Increased inflammatory cytokines owing to the liver partition have been reportedly responsible. If this were true, rapid liver hypertrophy should be achieved regardless of where the liver was split. A male Sprague-Dawley rat model was created, in which a liver split was placed inside the portal vein ligated lobe (PiLL), in addition to the ALPPS and portal vein ligation (PVL) models. Liver regeneration rate, inflammatory cytokine levels, activation status of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway and expressions of regenerating islet-derived (Reg)3α and Reg3β were investigated. The liver regeneration rate was significantly higher in the ALPPS group than in the PiLL group, whereas inflammatory cytokine levels were nearly equal. Additional volume increase in ALPPS group over PVL and PiLL groups was JAK2/STAT3-dependent. Reg3α and Reg3β expressions were observed only in the ALPPS group. An increase in inflammatory cytokines was not enough to describe the mechanism of rapid liver hypertrophy in ALPPS. Expressions of Reg3α and Reg3β could play an important role in conjunction with an activation of the JAK2/STAT3 pathway.

Evaluation of the effects of L-Theanine on neurobehavior in an adult male Sprague-Dawley Rat Model of PTSD

Post-traumatic stress disorder (PTSD) continues to be one of the most common mental health disorders in the United States and may occur in response to traumatic experiences. Currently, there are no interventions that prevent the development of PTSD. L-Theanine (L-Th), a major compound in green tea has been found to decrease anxiety and prevent memory impairment and may have potential effects in the prevention of PTSD. Sixty rats were divided into six experimental groups: control vehicle, control L-Th, control naïve, PTSD vehicle, PTSD Pre-L-Th (prophylactic), PTSD Post-L-Th (non-prophylactic). PTSD was induced by a 3-day restraint/tail shock stress model. The effects of L-Th on neurobehavior were evaluated by Elevated Plus-Maze (EPM), Morris Water Maze (MWM), and Forced Swim Test (FST). Our study found that the total food intake weight of PTSD Pre-L-Th (prophylactic) rats were significantly increased compared to that of PTSD vehicle rats (p = .04). Administration of L-Th 24 hours before the initial PTSD event or for 10 days following the last PTSD stress event did not statistically improve mean open arm exploration on the EPM, spatial memory, and learning in the MWM or behavioral despair measured by the FST (p &gt; 0.05). Although the 3-day restraint/tail shock stress model caused stress in the rodents, it did not produce reported PTSD-like anxiety and depression or spatial memory loss. The effect of Pre-L-Th or Post-L-Th treatment, on the neurobehavioral functions could not be effectively evaluated. However, this study provides a foundation for future studies to try different rodent PTSD models to induce PTSD-like neurobehavioral impairments to explore dosage, frequency, as well as the duration of L-Th administration before and/or after the post-traumatic event. The 3-day restraint/tail shock stress model caused stress in the rodents, Pre-L-Theanine treatment preconditioned the PTSD rats to endure stress.

PEDF protects cardiomyocytes by promoting FUNDC1‑mediated mitophagy via PEDF-R under hypoxic condition.

Pigment epithelial-derived factor (PEDF) is known to exert diverse physiological activities. Previous studies suggest that hypoxia could induce mitophagy. Astoundingly, under hypoxic condition, we found that PEDF decreased the mitochondrial density of cardiomyocytes. In this study, we evaluated whether PEDF could decrease the mitochondrial density and play a protective role in hypoxic cardiomyocytes via promoting mitophagy. Immunostaining and western blotting were used to analyze mitochondrial density and mitophagy of hypoxic cardiomyocytes. Gas chromatography-mass spectrometry and ELISA were used to analyze levels of palmitic acid and diacylglycerol. Transmission Electron Microscopy was used to detect mitophagy and the mitochondrial density in adult male Sprague-Dawley rat model of acute myocardial infarction. Compared to the control group, we observed that PEDF decreased mitochondrial density through promoting hypoxic cardiomyocyte mitophagy. PEDF increased the levels of palmitic acid and diacylglycerol, and then upregulated the levels of protein kinase Cα (PKC-α) and its activation. Furthermore, inhibition of PKC-α by Go6976 could effectively suppress PEDF-induced mitophagy. Besides, we found that PEDF promoted FUNDC1-mediated cardiomyocyte mitophagy via ULK1, which depended on the activation of PKC-α. Finally, we discovered that mitophagy was increased and mitochondrial density was reduced in adult male Sprague-Dawley rat model of acute myocardial infarction. We concluded that PEDF promotes mitophagy to protect hypoxic cardiomyocytes, through PEDF/PEDF-R/PA/DAG/PKC-α/ULK1/FUNDC1 pathway.

Neuroprotective effect of baicalin on focal cerebral ischemia in rats.

Baicalin, a flavonoid compound from the root of the herb Scutellaria baicalensis Georgi, has been widely used to treat patients with inflammatory disease. The aim of this study was to assess the efficacy of baicalin in a rat model of focal cerebral ischemia. Adult male Sprague-Dawley rat models of cerebral artery occlusion were established and then randomly and equally divided into three groups: ischemia (cerebral ischemia and reperfusion), valproic acid (cerebral ischemia and reperfusion + three intraperitoneal injections of valproic acid; positive control), and baicalin (cerebral ischemia and reperfusion + intraperitoneal injection of baicalin for 21 days). Neurological deficits were assessed using the postural reflex test and forelimb placing test at 3, 7, 14, and 21 days after ischemia. Rat cerebral infarct volume was measured using 2,3,5-triphenyltetrazolium chloride (TTC) staining method. Pathological change of ischemic brain tissue was assessed using hematoxylin-eosin staining. In the baicalin group, rat neurological function was obviously improved, cerebral infarct volume was obviously reduced, and the pathological impairment of ischemic brain tissue was obviously alleviated compared to the ischemia group. Cerebral infarct volume was similar in the valproic acid and baicalin groups. These findings suggest that baicalin has a neuroprotective effect on cerebral ischemia.

Validation of reference genes for quantitative gene expression analysis in experimental epilepsy.

To grasp the molecular mechanisms and pathophysiology underlying epilepsy development (epileptogenesis) and epilepsy itself, it is important to understand the gene expression changes that occur during these phases. Quantitative real-time polymerase chain reaction (qPCR) is a technique that rapidly and accurately determines gene expression changes. It is crucial, however, that stable reference genes are selected for each experimental condition to ensure that accurate values are obtained for genes of interest. If reference genes are unstably expressed, this can lead to inaccurate data and erroneous conclusions. To date, epilepsy studies have used mostly single, nonvalidated reference genes. This is the first study to systematically evaluate reference genes in male Sprague-Dawley rat models of epilepsy. We assessed 15 potential reference genes in hippocampal tissue obtained from 2 different models during epileptogenesis, 1 model during chronic epilepsy, and a model of noninjurious seizures. Reference gene ranking varied between models and also differed between epileptogenesis and chronic epilepsy time points. There was also some variance between the four mathematical models used to rank reference genes. Notably, we found novel reference genes to be more stably expressed than those most often used in experimental epilepsy studies. The consequence of these findings is that reference genes suitable for one epilepsy model may not be appropriate for others and that reference genes can change over time. It is, therefore, critically important to validate potential reference genes before using them as normalizing factors in expression analysis in order to ensure accurate, valid results.

Antinociceptive Effects of Botulinum Toxin Type A on Trigeminal Neuropathic Pain

Previous studies have demonstrated that botulinum toxin type A (BoNT-A) attenuates orofacial nociception. However, there has been no evidence of the participation of the voltage-gated sodium channels (Navs) in the antinociceptive mechanisms of BoNT-A. This study investigated the cellular mechanisms underlying the antinociceptive effects of BoNT-A in a male Sprague-Dawley rat model of trigeminal neuropathic pain produced by malpositioned dental implants. The left mandibular second molar was extracted under anesthesia, followed by a miniature dental implant placement to induce injury to the inferior alveolar nerve. Mechanical allodynia was monitored after subcutaneous injection of BoNT-A at 3, 7, or 12 d after malpositioned dental implant surgery. Subcutaneous injections of 1 or 3 U/kg of BoNT-A on postoperative day 3 significantly attenuated mechanical allodynia, although 0.3 U/kg of BoNT-A did not affect the air-puff threshold. A single injection of 3 U/kg of BoNT-A produced prolonged antiallodynic effects over the entire experimental period. Treatment with BoNT-A on postoperative days 7 and 12, when pain had already been established, also produced prolonged antiallodynic effects. Double treatments with 1 U/kg of BoNT-A produced prolonged, more antiallodynic effects as compared with single treatments. Subcutaneous administration of 3 U/kg of BoNT-A significantly inhibited the upregulation of Nav isoform 1.7 (Nav1.7) expression in the trigeminal ganglion in the nerve-injured animals. These results suggest that antinociceptive effects of BoNT-A are mediated by an inhibition of upregulated Nav1.7 expression in the trigeminal ganglion. BoNT-A is therefore a potential new therapeutic agent for chronic pain control, including neuropathic pain.

Blunted flow-mediated responses and diminished nitric oxide synthase expression in lymphatic thoracic ducts of a rat model of metabolic syndrome

Shear-dependent inhibition of lymphatic thoracic duct (TD) contractility is principally mediated by nitric oxide (NO). Endothelial dysfunction and poor NO bioavailability are hallmarks of vasculature dysfunction in states of insulin resistance and metabolic syndrome (MetSyn). We tested the hypothesis that flow-dependent regulation of lymphatic contractility is impaired under conditions of MetSyn. We utilized a 7-wk high-fructose-fed male Sprague-Dawley rat model of MetSyn and determined the stretch- and flow-dependent contractile responses in an isobaric ex vivo TD preparation. TD diameters were tracked and contractile parameters were determined in response to different transmural pressures, imposed flow, exogenous NO stimulation by S-nitro-N-acetylpenicillamine (SNAP), and inhibition of NO synthase (NOS) by l-nitro-arginine methyl ester (l-NAME) and the reactive oxygen species (ROS) scavenging molecule 4-hydroxy-tempo (tempol). Expression of endothelial NO synthase (eNOS) in TD was determined using Western blot. Approximately 25% of the normal flow-mediated inhibition of contraction frequency was lost in TDs isolated from MetSyn rats despite a comparable SNAP response. Inhibition of NOS with l-NAME abolished the differences in the shear-dependent contraction frequency regulation between control and MetSyn TDs, whereas tempol did not restore the flow responses in MetSyn TDs. We found a significant reduction in eNOS expression in MetSyn TDs suggesting that diminished NO production is partially responsible for impaired flow response. Thus our data provide the first evidence that MetSyn conditions diminish eNOS expression in TD endothelium, thereby affecting the flow-mediated changes in TD lymphatic function.

Ulinastatin Preconditioning Attenuates Inflammatory Reaction of Hepatic Ischemia Reperfusion Injury in Rats via High Mobility Group Box 1(HMGB1) Inhibition

Objective It has been found that ulinastatin (UTI) can attenuate hepatic injury in a rat model of ischemia reperfusion (IR), but the specific mechanism is unclear. This study aims to investigate possible pathomechanism of ulinastatin in reducing the inflammatory response after hepatic IR.Methods A male sprague-dawley(SD) rat model of hepatic ischemia reperfusion injury was used. The rats were randomly divided into 4 groups on average, which were 0.9% saline and IR group as control, ulinastatin preconditioning (UPC) group, UPC+rHMGB1 (recombinant HMGB1) group and UPC +anti-HMGB1 group. Serum aminotransferases, TNF-α, IL-1 and Myeloperoxidase (MPO) levels were measured. Histopathology examination and apoptotic cell detection and the different expression of HMGB1 protein were also assessed.Results Serum levels of aminotransferases, cytokines and hepatic MPO in UPC and UPC+anti-HMGB1 groups were significantly lower than those in control group (p<0.05). Decreased histologic damage and apoptosis were also seen in these two groups (p<0.05).Conclusions HMGB1 expressions in UPC and UPC+anti-HMGB1 groups were significantly lower than those in the two control groups (p<0.05), pretreatment with ulinastatin attenuated liver IR injury by reducing HMGB1 expression through its anti-inflammatory effects.

Exercise preconditioning-induced early and late phase of cardioprotection is associated with protein kinase C epsilon translocation.

Exercise preconditioning (EP) can provide powerful protection to the heart. Evidence supports the contention that EP directly enhances myocardial tolerance to ischaemia through a protein kinase C (PKC)-mediated mechanism. However, studies investigating the role of isoform-specific PKC after EP are lacking. In this study, a male Sprague-Dawley rat model of EP was established (4 periods of 30 m/min for 10 min exercise then a 10 min rest at 0% grade treadmill exercise). Rats were subjected to exhaustive exercise to induce myocardial injury. Chelerythrine (5 mg/kg) was injected before EP to investigate the role of PKC in EP. EP was found to attenuate exhaustive exercise-induced myocardial injury in both of EP's 2 protective phases, especially the latter phase. After EP, PKCε was markedly upregulated, and PKCε was translocated to myocardial intercalated disks, and p-PKCε(Ser729) was translocated to the myocardial cytomembrane. Even though PKCε was markedly upregulated and translocated to intercalated disks during exhaustive exercise, p-PKCε(Ser729) was mainly distributed in the cytoplasm. A chelerythrine injection before EP did not suppress the activation of PKC and the protection of EP. These results indicate that PKCε plays an important role in EP-mediated protection of the myocardium during exhaustive exercise-induced myocardial injury, and that a chelerythrine injection during exercise is not suitable for demonstrating the role of PKCε.

Effect of therapeutic hypothermia according to severity of sepsis in a septic rat model

Aim of studyThe effects of therapeutic hypothermia (HT) during experimental sepsis may be influenced by disease severity. We experimentally investigated the effect of therapeutic HT on varying disease severity in a septic rat model. Materials and methodsAn adult male Sprague-Dawley rat model of intra-abdominal sepsis was used. To modify the disease severity, we used two different models; a moderate severe sepsis model (MSSM) and a severe septic shock model (SSSM). All rats were randomized to a hypothermia group (HT, 30–32°C) or a normothermia group (NT, 36–38°C) 1h after sepsis induction in each model. HT was maintained for 4h and rewarming was conducted for 2h. Survival time was recorded for up to 12h in the SSSM group and 24h in the MSSM group. Acute lung and liver injury, cytokine, and malondialdehyde (MDA) levels were investigated 7h after sepsis induction. Hemodynamic profiles were also evaluated. ResultsIn the SSSM, there were survival benefits and reduced acute lung and liver injury with therapeutic HT. Therapeutic HT was also associated with significantly reduced levels of plasma interleukin-6 and tissue malondialdehyde (MDA) levels in the liver and lung compared with the NT group in the SSSM. There was a tendency for the mean arterial pressure to be higher in the HT group compared to the NT group in the SSSM. In MSSM, however, there was no such beneficial effect. ConclusionIn this rat model of severe septic shock, therapeutic HT showed beneficial effects. In contrast, therapeutic HT did not show protective effect in the moderate sepsis model.

Development and Analysis of a Collagen-Based Hemostatic Adhesive

Commercially available hemostatic-adhesive has the risk of disease transmission because it is derived from a plasma component. The purpose of this study is to manufacture a new hemostatic adhesive and evaluate its performances. Two atelocollagen-based hemostatic adhesives were produced and named as Bleestop A (2% esterified atelocollagen in 75% ethanol + 1% CaCl(2) + 0.71% DOPA + 0.1% tranexamic acid in DW) and Bleestop B (2% esterified atelocollagen in DW + 1% CaCl(2) + 0.71% DOPA + 0.1% aminocaproic acid in DW). These are compared with the negative control group (no adhesives used group) and the positive control group (Tissucol Duo Quick group). The adult male Sprague-Dawley rat model was adopted and the hemostatic-adhesion activities of each group were assessed by the adhesion strength test and the morphologic features of adhesion. The liver tissues were used. Histologic assessment of adhesion was accessed using light microscopy. Bleeding was controlled immediately after application of Bleestop A and partial adhesion was observed after 30 s. More than 95% area of the resected surface attached after 1 min. In Bleestop B, partial adhesion was observed after 30 s. More than 95% area of the resected surface was attached after 45 s. Histologic evaluation showed that Bleestop A and B mediated organized adhesion rapidly between both resected tissue surfaces. The adhesion strength of Bleestop A and B was better than the negative control group and showed same adhesion strength as the positive control group after 3 min. Bleestop A and B showed significant hemostasis and adhesion capability within 1 min. They are comparable to the positive control group.