Reperfusion Injury In Rats Research Articles

Melatonin pretreatment enhances the therapeutic effects of exogenous mitochondria against hepatic ischemia-reperfusion injury in rats through suppression of mitochondrial permeability transition.

We tested the hypothesis that melatonin (Mel) enhances exogenous mitochondria (Mito) treatment against rodent hepatic ischemia-reperfusion (IR) injury. In vitro study utilized three groups of hepatocytes (i.e. nontreatment, menadione, and menadione-melatonin treatment, 4.0 × 10(5) each), while in vivo study used adult male Sprague Dawley rats (n = 40) equally divided into sham-control (SC), IR (60-min left-lobe ischemia + 72-hr reperfusion), IR-Mel (melatonin at 30 min/6/8 hr after reperfusion), IR-Mito (mitochondria 15,000 μg/rat 30 min after reperfusion), and IR-Mel-Mito. Following menadione treatment in vitro, oxidative stress (NOX-1/NOX-2/oxidized protein), apoptotic (cleaved caspase-3/PARP), DNA damage (γ-H2AX/CD90/XRCC1), mitochondria damage (cytosolic cytochrome c) biomarkers, and mitochondrial permeability transition were found to be lower, whereas mitochondrial cytochrome c were found to be higher in hepatocytes with melatonin treatment compared to those without (all P < 0.001). In vivo study demonstrated highest liver injury score and serum AST in IR group, but lowest in SC group and higher in IR-Mito group than that in groups IR-Mel and IR-Mel-Mito, and higher in IR-Mel group than that in IR-Mel-Mito group after 72-hr reperfusion (all P < 0.003). Protein expressions of inflammatory (TNF-α/NF-κB/IL-1β/MMP-9), oxidative stress (NOX-1/NOX-2/oxidized protein), apoptotic (caspase-3/PARP/Bax), and mitochondria damage (cytosolic cytochrome c) biomarkers displayed an identical pattern, whereas mitochondria integrity marker (mitochondrial cytochrome c) showed an opposite pattern compared to that of liver injury score (all P < 0.001) among five groups. Microscopically, expressions of apoptotic nuclei, inflammatory (MPO(+) /CD68(+) /CD14(+) cells), and DNA damage (γ-H2AX(+) cells) biomarkers exhibited an identical pattern compared to that of liver injury score (all P < 0.001) among five groups. Melatonin-supported mitochondria treatment offered an additional benefit of alleviating hepatic IR injury.

Enriched Environment Enhances Poststroke Neurological Function Recovery on Rat: Involvement of p-ERK1/2

Increasing evidence shows that exposure to an enriched environment (EE) after cerebral ischemia or reperfusion injury is neuroprotective in animal models, including that EE enhances functional recovery after ischemic stroke. However, the mechanism underlying this effect remains unclear. To clarify this critical issue, the current study investigated the effects of EE on the role of extracellular signal-regulated kinase (ERK) after cerebral ischemia or reperfusion injury of rat. Adult rats were subjected to ischemia induced by middle cerebral artery occlusion (MCAO) followed by reperfusion. Ladder walking task and limb-use asymmetry task were used to test the recovery of rat behavior on postoperative days 1, 3, 5, 7, 14 and days 3, 7, 14, respectively. On the eighth day after MCAO, infarct volume was assessed by 2,3,5-triphenyltetrazolium chloride staining. Expressions of phosphorylated ERK1/2 (p-ERK1/2) and total ERK1/2 were examined by western blot, and electron microscopy was used to evaluate the astrocytes morphology surround in the perivascular 14 days after MCAO. EE improves the recovery of coordination and integration of motor movements on rats after cerebral ischemia or reperfusion injury. EE downregulates the level of p-ERK1/2 in the rat cortex after cerebral ischemia or reperfusion injury. Furthermore, EE reduces astrocytic swelling and injury. These findings suggest that EE could promote rehabilitation after ischemia via regulation of p-ERK1/2 expression, which may provide a therapeutic approach for cerebral ischemia or reperfusion injury. The suppression of postischemic astrocytic swelling in the brain of the ischemic rats through the intervention of EE would be one of the underlying mechanisms in the protective effect of cerebral ischemia.

The Effect of Erythropoietin on Ovarian Congestion during Ischemia Reperfusion Injury in Rats

The Effect of Erythropoietin on Ovarian Congestion during Ischemia Reperfusion Injury in Rats

Effects of CC-chemokine receptor 5 on ROCK2 and P-MLC2 expression after focal cerebral ischaemia–reperfusion injury in rats

Objective: CC-chemokine receptor 5 (CCR5) plays a pivotal role in reperfusion after stroke. This study assessed and confirmed the effects of CCR5 in experimental stroke via regulation of ROCK/P-MLC pathway.Methods: Male Sprague Dawley (SD) rats were randomly divided into sham group, ischaemia–reperfusion group (I/R group) and DAPTA group (I/R + CCR5 antagonist group). The rats of the I/R group were subjected to transient middle cerebral artery occlusion (tMCAO) for 2 hours, followed by 24 hours of reperfusion. Animals were measured for neurologic deficit, cerebral infarct volume, TUNEL and hematoxylin-eosin (HE) staining. The protein expressions of ROCK2 and P-MLC2(Ser19) were determined by western blot.Results: Pre-treatment with DAPTA displayed significantly improved neurological functional outcome and reduced cerebral lesion compared with the I/R group animals (p < 0.05); HE staining showed that the I/R group had severe neuronal damage in the ischaemia core and penumbral; Compared with the I/R group, ROCK2 and P-MLC2(Ser19) protein expression in the DAPTA group was reduced (p < 0.05).Conclusions: The data demonstrate that CCR5 is correlated with up-regulation of the expression of ROCK2 and P-MLC2(Ser19) in the ischaemia cortex. Treated with CCR5 antagonist protects the brain against focal cerebral ischaemia–reperfusion injury in rats.

Icariside II protects against cerebral ischemia–reperfusion injury in rats via nuclear factor-κB inhibition and peroxisome proliferator-activated receptor up-regulation

Icariside II (IRS) is a metabolite of icariin, which is derived from Herba Epimedii. Although the potential therapeutic effects of icariin on ischemic brain injury were well-investigated; the role of IRS in ischemic stroke is still not addressed clearly. Therefore, the current study aimed to evaluate the effects of IRS on cerebral ischemia–reperfusion injury in rats. The rats were pre-treated by IRS (10 or 30 mg kg−1, twice a day) for 3 days. After pre-treatment, a MCAO (middle cerebral artery occlusion) for 2 h followed by reperfusion for 24 h was applied on the rats to induce the cerebral ischemia injury model. The neurological deficit scores were assessed at 24 h after reperfusion, then animals were sacrificed, infarct volumes were determined by 2,3,5-triphenyltetrazolium chlorid (TTC) staining and protein expression levels of interleukin-1β (IL-1β), transforming growth factor-β1 (TGF-β1), inhibitory κB (IκB), nuclear factor κB (NF-κB) p65, peroxisome proliferator-activated receptor α (PPARα), and peroxisome proliferator-activated receptor γ (PPARγ) were assayed by using Western blot. IRS pretreatment markedly improved the neurological dysfunction and decreased infarct volume in MCAO rats. In addition, IRS inhibited IL-1β and TGF-β1 protein expression, and resulted in beneficial effects such as inhibition of IκB-α degradation and NF-κB activation induced by MCAO, in a dose-dependent manner. Furthermore, IRS increased the protein expression levels of PPARα and PPARγ in the ischemic brain. In conclusion, pretreatment with IRS protects against cerebral ischemic/reperfusion injury via up-regulation of PPARα and PPARγ and inhibition of NF-κB activation.

Curcumin Attenuates Inflammation, Oxidative Stress, and Ultrastructural Damage Induced by Spinal Cord Ischemia–Reperfusion Injury in Rats

Curcumin is a molecule found in turmeric root that possesses anti-inflammatory and antioxidant properties and has been widely used to treat neurodegenerative diseases. We investigated whether curcumin stimulates the neurorepair process and improves locomotor function in a rat model of spinal cord ischemia-reperfusion injury. Thirty-two Wistar albino rats (190-220 g) were randomly allocated into 4 groups of 8 rats each: 1 sham-operated group and 3 ischemia-reperfusion injury groups that received intraperitoneal injections of saline vehicle, methylprednisolone (MP, 30 mg/kg following induction of ischemia-reperfusion [IR] injury), or curcumin (200 mg/kg for 7 days before induction of IR injury). Spinal cord IR injury was induced by occlusion of the abdominal aorta for 30 minutes. After 24 hours of reperfusion, locomotor function was assessed using the Basso, Beattie, and Bresnahan scale. All animals were sacrificed. Spinal cord tissues were harvested to evaluate histopathological and ultrastructural alterations and to analyze levels of malondialdehyde, tumor necrosis factor-alpha, interleukin-1 beta, nitric oxide, and caspase-3, as well as enzyme activities of superoxide dismutase and glutathione peroxidase. Intraperitoneal administration of curcumin significantly reduced inflammatory cytokine expression, attenuated oxidative stress and lipid peroxidation, prevented apoptosis, and increased antioxidant defense mechanism activity in comparison to treatment with MP or saline. Histopathological and ultrastructural abnormalities were significantly reduced in curcumin-treated rats compared to the MP- and saline-treated groups. Furthermore, curcumin significantly improved locomotor function. Curcumin treatment preserves neuronal viability against inflammation, oxidative stress, and apoptosis associated with ischemia-reperfusion injury.

Metformin alleviated EMT and fibrosis after renal ischemia–reperfusion injury in rats

Purpose The purpose of this study is to assess the potential effects of metformin on the development of EMT and tubulointerstitial fibrosis 12 weeks after acute renal ischemia–reperfusion. Methods Male Sprague–Dawley rats were randomly assigned to four groups: Sham, IRI, transient administration of metformin (TAM), and continuous administration of metformin (CAM). Metformin was administered i.p. at a dose of 125 μg kg − 1 d − 1 3 d prior to suffering from IRI (TAM), or from 3 d before suffering from IRI to 12 weeks after reperfusion (CAM). Renal function, histology, and expressions of IL-6, TNF-α, α-SMA, TGF-β1, Vimentin, and E-cadherin were analyzed. Results Tubulointerstitial fibrosis worsened further in IRI, accompanied by the increased expressions of interleukin-6, TNF-α, α-SMA, TGF-β1, Vimentin, and loss of E-cadherin. Although there were no significant differences between IRI and TAM (p > 0.05). Compared with the IRI, expressions of IL-6, TNF-α, α-SMA, TGF-β1, and Vimentin were reduced and the expression of E-cadherin was restored in CAM (p < 0.05). CAM also significantly promoted activation of AMPK (p < 0.05), which showed no difference among Sham, IRI, and TAM (p > 0.05). Conclusions CAM significantly attenuated tubulointerstitial fibrosis and EMT in rats, potentially via activation of AMPK and down-regulation of TGF-β1.

The protective effect of dexmedetomidine against focal cerebral ischemia /reperfusion injury in rats and its mechanism

Objective To explore the neuroprotective effect of dexmedetomidine (Dex) in rats exposed to focal cerebral ischemia/reperfusion (I/R) induced by middle cerebral artery occlusion (MCAO) and the possible mechansims. Methods Adult male Sprague-Dawley rats were subjected to MCAO for 90 min followed by reperfusion for 24 h and Dex (15 μg·kg-1) was infused through the left femoral vein immediately after the onset of MCAO. The PI3K inhibitor LY294002 (LY, 10 mM, 10 μl) or eNOS inhibitor L-NIO (1 mg·kg-1, 10 μl) was intracerebroventricular administered before ischemia using a microinjecton. The neurological deficit score, brain edema, cerebral infarct volume, and neuron survivals were evaluated after 24 h of reperfusion. The expression of p-Akt (Ser473) and p-eNOS (Ser1177) in the ischemic hemicerebrum was detected by Western Blot. Results Compared with I/R group, the neurological deficit score, cerebral infarct volume, and the degree of brain edema were significantly reduced in the rats treated with Dex((2.3±0.4) vs (3.9±0.6), (19.3±3.5)% vs (40.5±5.4)%, (61.8±8.1)% vs (76.3±8.5)%, all P 0.05). Conclusion Dex can reduce cerebral injury in rats exposed to focal I/R, which is mediated by the activation of PI3K/Akt-eNOS pathway. Key words: Dexmedetomidine; Middle cerebral artery occlusion; PI3K; Akt; Endothelial nitric oxide sythanse

MiR-320a affects spinal cord edema through negatively regulating aquaporin-1 of blood-spinal cord barrier during bimodal stage after ischemia reperfusion injury in rats.

BackgroundSpinal cord edema is a serious complication and pathophysiological change after ischemia reperfusion (IR) injury. It has been demonstrated closely associated with bimodal disruption of blood–spinal cord barrier (BSCB) in our previous work. Aquaporin (AQP)1 plays important but contradictory roles in water homeostasis. Recently, microRNAs (miRs) effectively regulate numerous target mRNAs during ischemia. However, whether miRs are able to protect against dimodal disruption of BSCB by regulating perivascular AQP1 remains to be elucidated. ResultsSpinal water content and EB extravasation were suggested as a bimodal distribution in directly proportion to AQP1, since all maximal changes were detected at 12 and 48 h after reperfusion. Further TEM and double immunofluorescence showed that former disruption of BSCB at 12 h was attributed to cytotoxic edema by up-regulated AQP1 expressions in astrocytes, whereas the latter at 48 h was mixed with vasogenic edema with both endothelial cells and astrocytes involvement. Microarray analysis revealed that at 12 h post-injury, ten miRs were upregulated (>2.0 fold) and seven miRs were downregulated (<0.5 fold) and at 48 h, ten miRs were upregulated and eleven were downregulated compared to Sham-operated controls. Genomic screening and luciferase assays identified that miR-320a was a potential modulator of AQP1 in spinal cord after IR in vitro. In vivo, compared to rats in IR and negative control group, intrathecal infusion of miR-320a mimic attenuated IR-induced lower limb motor function deficits and BSCB dysfunction as decreased EB extravasation and spinal water content through down-regulating AQP1 expressions, whereas pretreated with miR-320a AMO reversed above effects. ConclusionThese findings indicate miR-320a directly and functionally affects spinal cord edema through negatively regulating AQP1 of BSCB after IR.

The Effect of the Antioxidant Drug ?U-74389G? On Oviductal Congestion during Ischemia Reperfusion Injury in Rats

The effect of the antioxidant drug “U-74389G” was examined, on rat model and particularly in an oviductal ischemia reperfusion (IR) protocol. The probable effects of that molecule were studied pathologically using oviductal congestion (OC) lesions. 40 rats of mean weight 231.875 g were used in the study. OC lesions were evaluated at 60 min of reperfusion (groups A and C) and at 120 min of reperfusion (groups B and D) in rats. U-74389G was administered only in groups C and D. U-74389G administration non-significantly altered the OC scores by 0 without lesions [-0.3582422 - 0.3582422] (p=0.9608). Reperfusion time non-significantly increased the OC scores by 0.2 without lesions [-0.1521699 - 0.5521699] (p= 0.2317). However, U-74389G administration and reperfusion time together significantly increased the OC scores by 0.0909091 without lesions [-0.1230462 - 0.3048644] (p=0.3951). U-74389G administration whether it interacted or not with reperfusion time failed to restore the OC lesions within short-term time context of 2 hours.

PI3K/Akt pathway contributes to neuroprotective effect of Tongxinluo against focal cerebral ischemia and reperfusion injury in rats

Ethnopharmacological relevanceTongxinluo (TXL), a compound prescription, is formulated according to the collateral disease doctrine of traditional Chinese medicine, and is widely used for the treatment of cardio-cerebrovascular diseases in China. Aim of the studyWe aimed to investigate the neuroprotective effect of TXL on focal cerebral ischemia and reperfusion injury in rats by attenuating its brain damage and neuronal apoptosis, and to assess the potential role of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway in this protection. Materials and methodsAdult Male Sprague-Dawley rats (n=120) were randomly divided into 5 groups: sham, cerebral ischemia and reperfusion (I/R), cerebral ischemia and reperfusion plus TXL (1.6g/kg/day) (TXL1.6), TXL1.6 plus LY294002 and dimethyl sulfoxide (DMSO) (TXL1.6+LY294002), TXL1.6 plus DMSO (TXL1.6+vehicle). Prior to the grouping, TXL1.6 was selected to be the optimal dose of TXL by evaluating the neurological deficits score of five group rats (Sham, I/R, TXL0.4, TXL0.8 and TXL1.6, n=30) at 0, 1, 3, 5, and 7 days after reperfusion. Rats, being subjected to middle cerebral artery occlusion (MCAO) for 90min followed by 24h reperfusion, were the cerebral ischemia/reperfusion models. At 24h after reperfusion, cerebral infarct area was measured via tetrazolium staining and neuronal damage was showed by Nissl staining. The double staining of Terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick end labeling (TUNEL) staining and immunofluorescence labeling with NeuN, was performed to evaluate neuronal apoptosis. Proteins involved in PI3K/Akt pathway were detected by Western blot. ResultsThe results showed that TXL markedly improved neurological function, reduced cerebral infarct area, decreased neuronal damage, and significantly attenuated neuronal apoptosis, while these effects were eliminated by inhibition of PI3K/Akt with LY294002. We also found that TXL up-regulated the expression levels of p-PDK1, p-Akt, p-c-Raf, p-BAD and down-regulated Cleaved caspase 3 expression notably, which were partially reversed by LY294002. Additionally, the increment of p-PTEN level on which LY294002 had little effect was also detected in response to TXL treatment. ConclusionsThese findings demonstrated that TXL provided neuroprotection against cerebral ischemia/reperfusion injury and neuronal apoptosis, and this effect was mediated partly by activation of the PI3K/Akt pathway.

Ischemic Postconditioning Assessment in the Liver of Rats Undergoing Mesenteric Ischemia and Reperfusion.

IntroductionIschemic postconditioning is a method that shows evidence of efficacy in minimizing reperfusion injury; however, its effectiveness in preventing injuries in distant organs is still unknown, especially in those who have undergone mesenteric ischemia and reperfusion.ObjectiveTo evaluate the effect of ischemic postconditioning in preventing reperfusion injury in the liver of rats submitted to mesenteric ischemia and reperfusion, comparing two different methods of ischemic postconditioning.Methods30 Wistar male rats were used, distributed into three groups: Group A: Ten rats submitted to intestinal ischemia for 30 minutes followed by reperfusion for 60 minutes; Group B: Ten rats subjected to ischemia and reperfusion; after ischemia, two cycles of reperfusion (two minutes each) interleaved with two cycles of ischemia (two minutes each); and Group C: Ten rats subjected to ischemia and reperfusion; after ischemia, four cycles of reperfusion (30 seconds each) interspersed with four cycles of ischemia (30 seconds each). After the experiment, the left lobe of the liver was resected for subsequent histological analysis, using the following classification: grade 1 - centrilobular congestion; grade 2 - centrilobular congestion with some degeneration of hepatocytes in one or two central veins; and grade 3 - multifocal centrilobular congestion and degeneration of portal hepatocytes.ResultsThe mean degree of liver damage found was 1.8 in group A, 1.7 in group B and 1.3 in group C. There was no statistically significant difference between the groups.ConclusionIschemic postconditioning was unable to minimize reperfusion injury in rats undergoing mesenteric ischemia and reperfusion.

Is Chronic Curcumin Supplementation Neuroprotective Against Ischemia for Antioxidant Activity, Neurological Deficit, or Neuronal Apoptosis in an Experimental Stroke Model?

To investigate the neuroprotective effect of chronic curcumin supplementation on the rat forebrain prior to ischemia and reperfusion. Forebrain ischemia was induced by bilateral common carotid artery occlusion for 1/2 hour, followed by reperfusion for 72 hours. Older rats were divided into five groups: Group I received 300 mg/kg oral curcumin for 21 days before ischemia and 300 mg/kg intraperitoneal curcumin after ischemia; Group II received 300 mg/kg intraperitoneal curcumin after ischemia; Group III received 300 mg/kg oral curcumin for 21 days before ischemia; Group IV had only ischemia; Group V was the sham-operated group. The forebrain was rapidly dissected for biochemical parameter assessment and histopathological examination. In forebrain tissue, enzyme activities of superoxide dismutase, glutathione peroxidase, and catalase were significantly higher in Group I than Groups II or III (p < 0.05) while xanthine dehydrogenase and malondialdehyde enzyme activities and concentrations of interleukin-6 and TNF-alpha were significantly lower in Group I when compared to Groups II and III (p < 0.05). A significant reduction in neurological score was observed after 24 and 72 hours in the curcumin-treated groups compared with the ischemic group. We also found a marked reduction in apoptotic index after 72 hours in the groups receiving curcumin. Significantly more TUNEL-positive cells were observed in the ischemic group compared to those treated with curcumin. We demonstrated the neuroprotective effect of chronic curcumin supplement on biochemical parameters, neurological scores and apoptosis following ischemia and reperfusion injury in rats.

The effect of the antioxidant drug "U-74389G" on amylase during ischemia reperfusion injury in rats

Background: This experimental study examined the effect of the antioxidant drug U-74389G on a rat model and particularly in an ischemia-reperfusion protocol. Settings and Design: The beneficial effect or noneffectiveness of that molecule was studied biochemically using blood mean amylase (A) levels. Materials and Methods: Forty rats of mean weight 231.875 g were used in the study. The levels were measured at 60 min of reperfusion (Groups A and C) and at 120 min of reperfusion (Groups B and D) with the administration of the drug U-74389G in Groups C and D. Results: U-74389G administration significantly decreased the predicted A levels by 8.40 ± 2.02% ( P = 0.0001). Reperfusion time kept nonsignificantly increased the predicted A levels by 1.68 ± 2.44% ( P = 0.4103). However, U-74389G administration and reperfusion time together produced a significant combined effect in keeping decreased the predicted A levels by 4.67 ± 1.26% ( P = 0.0005). Conclusions: U-74389G administration whether it interacted or not with reperfusion time has a significant decreasing beneficial restoring short-term effect on amylase levels.

The effect of the antioxidant drug &amp;#147;U-74389G&amp;#148; on acid phosphatase levels during ischemia reperfusion injury in rats

Introduction: This experimental study examined the effect of the antioxidant drug “U-74389G”, on a rat model and particularly in an ischemia - reperfusion protocol. The effects of that molecule were studied biochemically using blood mean acid phosphatase (ACP) levels. Methods: 40 rats of mean weight 231.875 g were used in the study. ACP levels were measured at 60 min of reperfusion (groups A and C) and at 120 min of reperfusion (groups B and D). Administration of the drug U-74389G was predicted only for groups C and D. Results: U-74389G administration significantly decreased the ACP levels by 128.45%+14.84% (p= 0.0000). Reperfusion time non-significantly decreased the ACP levels by 22.44%+25.86% (p= 0.2000). However, U-74389G administration and reperfusion time together significantly decreased the ACP levels by 74.45%+9.63% (p= 0.0000). Conclusions: U-74389G administration whether it interacted or not with reperfusion time, offers spectacular significant decreasing short – term effects on ACP levels.

Protective Role of Ramipril and Candesartan against Myocardial Ischemic Reperfusion Injury: A Biochemical and Transmission Electron Microscopical Study.

The present study was designed to investigate the role of combined administration of Ramipril and Candesartan against in vitro myocardial ischemic reperfusion injury in rat. Male Wistar albino rats were divided into five groups (n = 6) and treated with saline (10 mL/kg), Ramipril (2 mg/kg), Candesartan (1 mg/kg), and the combination of both drugs, respectively 24 h before induction of global ischemia (5 min of stabilization, 9 min of global ischemia, and 12 min of reflow). Combination of Ramipril and Candesartan when compared to the monotherapy significantly increased the levels of superoxide dismutase, reduced glutathione, catalase, and nitric oxide and decreased the levels of thiobarbituric acid reactive substances. In addition, the superior protective role of combination of Ramipril and Candesartan on ischemia induced myocardial damage was further confirmed by well preserved myocardial tissue architecture in light microscopy and transmission electron microscopy analysis studies. The combination was proved to be effective in salvaging the myocardial tissue against ischemic reperfusion injury when compared to the monotherapy of individual drugs and further investigations on protective mechanism of drugs by increasing the nitric oxide level at molecular levels are needed.

The Effect of Erythropoietin on Potassium Levels During Ischemia Reperfusion Injury in Rats

The aim of this experimental study was to examine the effect of erythropoietin on a rat model and particularly a hypoxia reoxygenation (HR) protocol. The effect of that molecule was studied biochemically using blood mean potassium (K) levels. Materials and methods: 40 rats of mean weight 247.7g were used in the study. Potassium levels were measured at 60minute (groups A and C) and at 120minute (groups B and D) of reoxygenation. Erythropoietin (Epo) was administered only in groups C and D. Results: Erythropoietin administration decreased the potassium levels insignificantly by 2.21%±3.66% (P=0.5134). Reoxygenation time increased the potassium levels insignificantly by 3.58%±3.63% (P=0.3375). The interaction of erythropoietin administration and reoxygenation time increased the potassium levels insignificantly by 0.18%±2.22% (P= 0.9338). Conclusion: Erythropoietin administration; re-oxygenation time and their interaction have miscellaneous insignificant effects on potassium levels on the narrow context of 2 hours. Perhaps, a longer study time or a higher Epo dose may have clearer and significant effects.

Effects and Mechanism of Action of Inducible Nitric Oxide Synthase on Apoptosis in a Rat Model of Cerebral Ischemia-Reperfusion Injury.

Inducible nitric oxide synthase (iNOS) is a key enzyme in regulating nitric oxide (NO) synthesis under stress, and NO has varying ability to regulate apoptosis. The aim of this study was to investigate the effects and possible mechanism of action of iNOS on neuronal apoptosis in a rat model of cerebral focal ischemia and reperfusion injury in rats treated with S-methylisothiourea sulfate (SMT), a high-selective inhibitor of iNOS. Seventy-two male Sprague-Dawley (SD) rats were randomly divided into three groups: the sham, middle cerebral artery occlusion (MCAO) + vehicle, and MCAO + SMT groups. Neurobehavioral deficits, infarct zone size, and cortical neuron morphology were evaluated through the modified Garcia scores, 2,3,5-triphenyltetrazolium chloride (TTC), and Nissl staining, respectively. Brain tissues and serum samples were collected at 72 hr post-reperfusion for immunohistochemical analysis, Western blotting, Terminal deoxynucleotidyl transferase-mediated dUTP-biotin Nick End Labeling assay (TUNEL) staining, and enzyme assays. The study found that inhibition of iNOS significantly attenuated the severity of the pathological changes observed as a result of ischemia-reperfusion injury: SMT reduced NO content as well as total nitric oxide synthase (tNOS) and iNOS activities in both ischemic cerebral hemisphere and serum, improved neurobehavioral scores, reduced mortality, reduced the infarct volume ratio, attenuated morphological changes in cortical neurons, decreased the rate of apoptosis (TUNEL and caspase-3-positive), and increased phospho (p)-AKT expression in ischemic penumbra. These results suggested that inhibition of iNOS might reduce the severity of ischemia-reperfusion injury by inhibiting neuronal apoptosis via maintaining p-AKT activity.

The expression of response gene to complement 32 on renal ischemia reperfusion injury in rat

To investigate the expression of response gene to complement 32 (RGC32) in rat with acute kidney injury (AKI) and to explore the role of RGC32 in renal injury and repair induced by ischemia reperfusion. Rats were randomly divided into two groups, including sham operation group (n = 48) and acute ischemia reperfusion injury (IRI) group (n = 48). Rats were sacrificed following reperfusion 2 h, 6 h, 24 h, 48 h, 72 h, 1 week (w), 2 w, and 4 w. The distribution and expression of RGC32 in renal tissue were observed by means of immunohistochemistry. The mean density of the images detected by Image-Pro Plus 6 was designated as the representative RGC32 expression levels. Meanwhile, RGC32 mRNA expression was measured by qPCR. RGC32 mainly expressed in cytoplasm of proximal tubular epithelial cells. However, RGC32 did not express in renal interstitium and vessels. The expression levels of RGC32 measured by immunohistochemistry at different reperfusion time were 0.0168 ± 0.0029, 0.0156 ± 0.0021, 0.0065 ± 0.0013, 0.0075 ± 0.0013, 0.0096 ± 0.0014, 0.0132 ± 0.0016, 0.0169 ± 0.0014, 0.0179 ± 0.0022, respectively. Compared with the sham group, the level of RGC32 expression in IRI group was significant lower at 24 h, 48 h, 72 h after IRI (p < 0.05). The expression levels of RGC32 mRNA at different reperfusion time measured by qPCR were corroborated the immunohistochemistry finding. The in vitro experiments show the expression of α-SMA and extracellular matrix expression increased signification when the RGC32 was silenced. Our data showed that the RGC32 expression in AKI rat decreased significantly reduces with different reperfusion time and performs a time-dependent manner. RGC32 may play an important role in the pathogenesis of AKI following IRI and repair in rat.

The Long-Term Consumption of Ginseng Extract Reduces the Susceptibility of Intermediate-Aged Hearts to Acute Ischemia Reperfusion Injury.

BackgroundA large number of experimental studies using young adult subjects have shown that ginseng (Panax ginseng C.A. Meyer) protects against ischemia heart disease. However, ginseng has not been explored for its anti-I/R effect and mechanism of action in the aged myocardium. The present study was designed to evaluate the effects of the long-term consumption of ginseng extract on myocardial I/R in an in vivo rat model and explore the potential underlying mechanism.Methods and ResultsYoung (6-mo-old) and intermediate-aged (18-mo-old) rats were gavaged with either standardized ginseng extract (RSE) at 80 mg/kg or vehicle for 90 days. The rats were sacrificed after LAD coronary artery ligation was performed to induce 30 min of ischemia, followed by 90 min of reperfusion. The myocardial infarct size was measured. Left ventricular function was evaluated using pressure-volume loops. The levels of survival, apoptotic and longevity protein expression were assessed through Western blot analysis. Myocardial pathology was detected through H&E or Masson’s trichrome staining. We observed higher infarct expansion with impairment in the LV functional parameters, such as LVSP and LVEDP, in aged rats compared with young rats. Enhanced Akt phosphorylation and eNOS expression in RSE-treated aged hearts were accompanied with reduced infarct size, improved cardiac performance, and inducted survival signals. In contrast, p-Erk and caspase 7 were significantly downregulated in aged rats, suggesting that cardiomyocyte apoptosis was suppressed after RSE treatment. RSE also inhibited caspase-3/7 activation and decreased Bax/Bcl-2 ratio. Consistent with the results of apoptosis, Sirt1 and Sirt3 were significantly increased in the RSE-treated aged heart compared with vehicle-treated I/R, suggesting that the anti-aging effect was correlated with the anti-apoptotic activity of RSE.ConclusionThese findings suggest that the long-term consumption of ginseng extract reduced the susceptibility of intermediate-aged hearts to acute ischemia reperfusion injury in rats. These effects might be mediated through the activation of Akt/eNOS, suppression of Erk/caspase 7 and upregulation of Sirt1 and Sirt3 in intermediate-aged rats.