Postischemic cardiac recovery in heme oxygenase‐1 transgenic ischemic/reperfused mouse myocardium

Heme oxygenase-1 (HO-1) transgenic mice (Tg) were created using a rat HO-1 genomic transgene. Transgene expression was detected by RT-PCR and Western blots in the left ventricle (LV), right ventricle (RV) and septum (S) in mouse hearts, and its function was demonstrated by the elevated HO enzyme activity. Tg and non-transgenic (NTg) mouse hearts were isolated and subjected to ischemia/reperfusion. Significant post-ischemic recovery in coronary flow (CF), aortic flow (AF), aortic pressure (AOP) and first derivative of AOP (AOPdp/dt) were detected in the HO-1 Tg group compared to the NTg values. In HO-1 Tg hearts treated with 50 μmol/kg of tin protoporphyrin IX (SnPPIX), an HO enzyme inhibitor, abolished the post-ischemic cardiac recovery. HO-1 related carbon monoxide (CO) production was detected in NTg, HO-1 Tg and HO-1 Tg + SnPPIX treated groups, and a substantial increase in CO production was observed in the HO-1 Tg hearts subjected to ischemia/reperfusion. Moreover, in ischemia/reperfusion-induced tissue Na⁺ and Ca²⁺ gains were reduced in HO-1 Tg group in comparison with the NTg and HO-1 Tg + SnPPIX treated groups; furthermore K⁺ loss was reduced in the HO-1 Tg group. The infarct size was markedly reduced from its NTg control value of 37 ± 4% to 20 ± 6% (P < 0.05) in the HO-1 Tg group, and was increased to 47 ± 5% (P < 0.05) in the HO-1 knockout (KO) hearts. Parallel to the infarct size reduction, the incidence of total and sustained ventricular fibrillation were also reduced from their NTg control values of 92% and 83% to 25% (P < 0.05) and 8% (P < 0.05) in the HO-1 Tg group, and were increased to 100% and 100% in HO-1 KO^−/− hearts. Immunohistochemical staining of HO-1 was intensified in HO-1 Tg compared to the NTg myocardium. Thus, the HO-1 Tg mouse model suggests a valuable therapeutic approach in the treatment of ischemic myocardium.     

Ischemic preconditioning in isolated perfused mouse heart: Reduction in infarct size without improvement of post-ischemic ventricular function

Genetically engineered mice provide an excellent tool to study the role of a particular gene in biological systems and will be increasingly used as models to understand the signal transduction mechanisms involved in ischemic preconditioning (IP). However, the phenomenon of IP has not been well characterized in this species. We therefore attempted to examine whether IP could protect isolated mouse heart against global ischemia/reperfusion (GI/R) injury. Thirty adult mice hearts were perfused at constant pressure of 55 mmHg in Langendorff mode. Following 20 min equilibration, the hearts were randomized into three groups (n = 10/each): (1) Control Group; (2) IP2.5 Group: IP with two cycles of 2.5 min GI + 2.5 min R; (3) IP5 Group: IP with 5 min GI + 5 min R. All hearts were then subjected to 20 min of GI and 30 min R (37°C). Ventricular developed force was measured by a force transducer attached to the apex. Leakage of CK and LDH was measured in coronary efflux. Infarct size was determined by tetrazolium staining. Following sustained GI/R, infarct size was significantly reduced in IP2.5 (13.8 ± 2.3%), but not in IP5 (20.1 ± 4.0%), when compared with non-preconditioned control (23.6 ± 3.8%) hearts. CK and LDH release was also reduced in both IP2.5 and IP5 groups. No significant improvement in post-ischemic ventricular contractile function was observed in either IP groups. We conclude that IP with repetitive cycles of brief GI/R is able to reduce myocardial infarct size and intracellular enzyme leakage caused by a sustained GI/R in the isolated perfused mouse heart. This anti-necrosis cardioprotection induced by IP was not associated with the amelioration of post-ischemic ventricular dysfunction.     

GRP78 effectively protect hypoxia/reperfusion‐induced myocardial apoptosis via promotion of the Nrf2/HO‐1 signaling pathway

Myocardial infarction is a major cause of death worldwide. Despite our understanding of the pathophysiology of myocardial infarction and the therapeutic options for treatment have improved substantially, acute myocardial infarction remains a leading cause of morbidity and mortality. Recent findings revealed that GRP78 could protect myocardial cells against ischemia reperfusion injury‐induced apoptosis, but the exact function and molecular mechanism remains unclear. In this study, we aimed to explore the effects of GRP78 on hypoxia/reperfusion (H/R)‐induced cardiomyocyte injury. Intriguingly, we first observed that GRP78 overexpression significantly protected myocytes from H/R‐induced apoptosis. On mechanism, our work revealed that GRP78 protected myocardial cells from hypoxia/reperfusion‐induced apoptosis via the activation of the Nrf2/HO‐1 signaling pathway. We observed the enhanced expression of Nrf2/HO‐1 in GRP78 overexpressed H9c2 cell, while GRP78 deficiency dramatically antagonized the expression of Nrf2/HO‐1. Furthermore, we found that blocked the Nrf2/HO‐1 signaling by the HO‐1 inhibitor zinc protoporphyrin IX (Znpp) significantly retrieved H9c2 cells apoptosis that inhibited by GRP78 overexpression. Taken together, our findings revealed a new mechanism by which GRP78 alleviated H/R‐induced cardiomyocyte apoptosis in H9c2 cells via the promotion of the Nrf2/HO‐1 signaling pathway.     

Neuroprotective effects of 1‐O‐hexyl‐2,3,5‐trimethylhydroquinone on ischaemia/reperfusion‐induced neuronal injury by activating the Nrf2/HO‐1 pathway

1‐O‐Hexyl‐2,3,5‐trimethylhydroquinone (HTHQ), a lipophilic phenolic agent, has an antioxidant activity and reactive oxygen species (ROS) scavenging property. However, the role of HTHQ on cerebral ischaemic/reperfusion (I/R) injury and the underlying mechanisms remain poorly understood. In the present study, we demonstrated that HTHQ treatment ameliorated cerebral I/R injury in vivo, as demonstrated by the decreased infarct volume ration, neurological deficits, oxidative stress and neuronal apoptosis. HTHQ treatment increased the levels of nuclear factor erythroid 2–related factor 2 (Nrf2) and its downstream antioxidant protein, haeme oxygenase‐1 (HO‐1). In addition, HTHQ treatment decreases oxidative stress and neuronal apoptosis of PC12 cells following hypoxia and reperfusion (H/R) in vitro. Moreover, we provided evidence that PC12 cells were more vulnerable to H/R‐induced oxidative stress after si‐Nrf2 transfection, and the HTHQ‐mediated protection was lost in PC12 cells transfected with siNrf2. In conclusion, these results suggested that HTHQ possesses neuroprotective effects against oxidative stress and apoptosis after cerebral I/R injury via activation of the Nrf2/HO‐1 pathway.     

Effects of L-carnitine and its derivatives on postischemic cardiac function,ventricular fibrillation and necrotic and apoptotic cardiomyocyte death in isolated rat hearts

The study aimed to examine whether L-carnitine and its derivatives, acetyl-L-carnitine and propionyl-L-carnitine, were equally effective and able to improve postischemic cardiac function, reduce the incidence of reperfusion-induced ventricular fibrillation, infarct size, and apoptotic cell death in ischemic/reperfused isolated rat hearts. There are several studies indicating that L-carnitine, a naturally occurring amino acid and an essential cofactor, can improve mechanical function and substrate metabolism not only in hypertrophied or failing myocardium but also in ischemic/reperfused hearts. The effects of L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine, on the recovery of heart function, incidence of reperfusion-induced ventricular fibrillation (VF), infarct size, and apoptotic cell death after 30 min ischemia followed by 120 min reperfusion were studied in isolated working rat hearts. Hearts were perfused with various concentrations of L-carnitine (0.5 and 5 mM), acetyl-L-carnitine (0.5 and 5 mM), and propionyl-L-carnitine (0.05, 0.5, and 5 mM), respectively, for 10 min before the induction of ischemia. Postischemic recovery of CF, AF, and LVDP was significantly improved in all groups perfused with 5 mM of L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine. Significant postischemic ventricular recovery was noticed in the hearts perfused with 0.5 mM of propionyl-L-carnitine, but not with the same concentration of L-carnitine or L-acetyl carnitine. The incidence of reperfusion VF was reduced from its control value of 90 to 10% (p < 0.05) in hearts perfused with 5 mM of propionyl-L-carnitine only. Other doses of various carnitines failed to reduce the incidence of VF. The protection in CF, AF, LVDP, and VF reflected in a reduction in infarct size and apoptotic cell death in hearts treated with various concentrations of carnitine derivatives. The difference between effectiveness of various carnitines on the recovery of postischemic myocardium may be explained by different membrane permeability properties of carnitine and its derivatives.     

钠泵功能改变及内质网应激在大鼠离体心脏缺血/再灌注损伤中的作用

目的：探讨钠泵活性改变及内质网应激（ERS）在大鼠离体心脏再灌损伤中的作用及其机制。方法：将60只雄性SD大鼠随机分为6组（n=10）：正常对照组（NC组）、缺血/再灌损伤组（I/R组）、哇巴因-缺血/再灌损伤组（OUA-I/R组）、地高辛抗血清-缺血/再灌损伤组（Anti-Dig-I/R组）、Src抑制剂PP2-哇巴因-缺血/再灌损伤组（PP2-OUA-I/R组）、PLC抑制剂U73122-哇巴因-缺血/再灌损伤组（U73122-OUA-I/R组）。建立全心缺血30 min,再灌注120min的Langendorff大鼠离体心脏缺血再灌损伤模型。检测各组相同时间点心功能恢复率、冠脉流出液中乳酸脱氢酶（LDH）和肌酸激酶（CK）活性,心肌中Na⁺-K⁺-ATP酶活性和钙离子水平。流式细胞仪检测心肌细胞凋亡率,Western blot检测心肌钠泵α1亚基、葡萄糖调节蛋白78（GRP78）、C/EBP同源蛋白（CHOP）及凋亡蛋白Bcl-2/Bax的表达。结果：与I/R组相比,给予哇巴因预处理可使心功能恢复率明显下降,心肌酶漏出增多,Na⁺-K⁺-ATP酶的活性降低,心肌细胞内钙水平升高,细胞凋亡率增多,心肌钠泵α1亚基和Bcl-2表达降低,GRP78、CHOP和Bax表达升高;而Anti-Dig-I/R组与I/R组相比各指标均明显改善;给予Src抑制剂PP2或PLC抑制剂U73122后,哇巴因对心肌的损伤作用被部分阻断,表现为心功能恢复率升高,心肌酶漏出减少,Na⁺-K⁺-ATP酶的活性明显恢复,Ca²⁺水平下降,细胞凋亡率下降,心肌钠泵α₁亚基和Bcl-2表达增多,GRP78和Bax表达减少。结论：钠泵功能改变和内质网应激共同参与大鼠离体心脏缺血再灌损伤,钠泵通路（Src和PLC）介导内质网应激是引起大鼠离体心脏缺血再灌损伤细胞凋亡机制之一。     

The apolipoprotein A‐I mimetic peptide,D‐4F,restrains neointimal formation through heme oxygenase‐1 up‐regulation

D‐4F, an apolipoprotein A‐I (apoA‐I) mimetic peptide, possesses distinctly anti‐atherogenic effects. However, the biological functions and mechanisms of D‐4F on the hyperplasia of vascular smooth muscle cells (VSMCs) remain unclear. This study aimed to determine its roles in the proliferation and migration of VSMCs. In vitro, D‐4F inhibited VSMC proliferation and migration induced by ox‐LDL in a dose‐dependent manner. D‐4F up‐regulated heme oxygenase‐1 (HO‐1) expression in VSMCs, and the PI3K/Akt/AMP‐activated protein kinase (AMPK) pathway was involved in these processes. HO‐1 down‐regulation with siRNA or inhibition with zinc protoporphyrin (Znpp) impaired the protective effects of D‐4F on the oxidative stress and the proliferation and migration of VSMCs. Moreover, down‐regulation of ATP‐binding cassette transporter A1 (ABCA1) abolished the activation of Akt and AMPK, the up‐regulation of HO‐1 and the anti‐oxidative effects of D‐4F. In vivo, D‐4F restrained neointimal formation and oxidative stress of carotid arteries in balloon‐injured Sprague Dawley rats. And inhibition of HO‐1 with Znpp decreased the inhibitory effects of D‐4F on neointimal formation and ROS production in arteries. In conclusion, D‐4F inhibited VSMC proliferation and migration in vitro and neointimal formation in vivo through HO‐1 up‐regulation, which provided a novel prophylactic and therapeutic strategy for anti‐restenosis of arteries.     

Neuroprotective effects of Argon are mediated via an ERK‐1/2 dependent regulation of heme‐oxygenase‐1 in retinal ganglion cells

Retinal ischemia and reperfusion injuries (R‐IRI) damage neuronal tissue permanently. Recently, we demonstrated that Argon exerts anti‐apoptotic and protective properties. The molecular mechanism remains unclear. We hypothesized that Argon inhalation exert neuroprotective effects in rats retinal ganglion cells (RGC) via an ERK‐1/2 dependent regulation of heat‐shock proteins. Inhalation of Argon (75 Vol%) was performed after R‐IRI on the rats′ left eyes for 1 h immediately or with delay. Retinal tissue was harvested after 24 h to analyze mRNA and protein expression of heat‐shock proteins ?70, ?90 and heme‐oxygenase‐1, mitogen‐activated protein kinases (p38, JNK, ERK‐1/2) and histological changes. To analyze ERK dependent effects, the ERK inhibitor PD98059 was applicated prior to Argon inhalation. RGC count was analyzed 7 days after injury. Statistics were performed using anova . Argon significantly reduced the R‐IRI‐affected heat‐shock protein expression (p < 0.05). While Argon significantly induced ERK‐1/2 expression (p < 0.001), inhibition of ERK‐1/2 before Argon inhalation resulted in significantly lower vital RGCs (p < 0.01) and increase in heme‐oxygenase‐1 (p < 0.05). R‐IRI‐induced RGC loss was reduced by Argon inhalation (p < 0.001). Immunohistochemistry suggested ERK‐1/2 activation in Müller cells. We conclude, that Argon treatment protects R‐IRI‐induced apoptotic loss of RGC via an ERK‐1/2 dependent regulation of heme‐oxygenase‐1.

     

Increased infarct size and exacerbated apoptosis in the glutathione peroxidase-1 (Gpx-1) knockout mouse brain in response to ischemia/reperfusion injury

Glutathione peroxidase is an antioxidant enzyme that is involved in the control of cellular oxidative state. Recently, unregulated oxidative state has been implicated as detrimental to neural cell viability and involved in both acute and chronic neurodegeneration. In this study we have addressed the importance of a functional glutathione peroxidase in a mouse ischemia/reperfusion model. Two hours of focal cerebral ischemia followed by 24 h of reperfusion was induced via the intraluminal suture method. Infarct volume was increased three-fold in the glutathione peroxidase-1 (Gpx-1) -/- mouse compared with the wild-type mouse; this was mirrored by an increase in the level of apoptosis found at 24 h in the Gpx-1 -/- mouse compared with the wild-type mouse. Neuronal deficit scores correlated to the histologic data. We also found that activated caspase-3 expression is present at an earlier time point in the Gpx-1 -/- mice when compared with the wild-type mice, which suggests an enhanced susceptibility to apoptosis in the Gpx-1 -/- mouse. This is the first known report of such a dramatic increase, both temporally and in level of apoptosis in a mouse stroke model. Our results suggest that Gpx-1 plays an important regulatory role in the protection of neural cells in response to the extreme oxidative stress that is released during ischemia/reperfusion injury.     

血红素氧合酶-1在离体大鼠心肌缺血预适应中的作用

目的:分别观察给予HO-1诱导剂和抑制剂对心肌相对缺血再灌注损伤和缺血预适应的影响,探讨HO-1在缺血预适应中的作用.方法:实验动物随机分为对照组(CN)、缺血/再灌损伤组(I/R)、缺血预适应 缺血/再灌损伤组(PC)、HO-1诱导剂 缺血/再灌损伤组(HM)、HO-1抑制剂 缺血预适应组(ZP).心肌缺血/再灌损伤采用相对缺血/再灌损伤模型,缺血预适应则为相对缺血5min恢复5min,反复2次.测定心功能、MDA及HO-1活性变化.结果:HM组HO-1活性升高,心功能恢复率均显著高于IR组(P＜0.01),MDA含量显著低于IR组(P＜0.05).ZP组活性降低,心功能恢复率显著低于PC组(P＜0.05),MDA含量显著高于PC组(P＜0 05).结论:HO-1是缺血预适应释放的内源性活性物质之一.     

Effects of L-carnitine on mechanical recovery of isolated rat hearts in relation to the perfusion with glucose and palmitate

The purpose of this study was to investigate the effects of L-carnitine on the hemodynamic parameters of Langendorff hearts. Isolated rat hearts were perfused with various solutions containing high or low concentrations of fatty acids, additional glucose or no glucose, and L-carnitine or no L-carnitine. The most interesting part of the experiments was the behaviour of the hearts in the reperfusion period after no-flow ischemia of 20 min. The results were: (1) With glucose and high fatty acid concentrations the hearts showed an improved recovery of the left ventricular functions in the reperfusion period compared with low fatty acid concentrations. Without glucose the left ventricular pressure is much lower in the reperfusion period. (2) Addition of L-carnitine improved the recovery of the ischemically damaged hearts. This improvement is especially impressive at low fatty acid concentrations. L-carnitine addition at high fatty acid concentrations but without glucose strongly improved reperfusion behaviour. (3) The coronary flow is increased by 2 experimental conditions: (i) perfusion at low levels of fatty acids, carnitine and with glucose and (ii) high levels of fatty acids and carnitine but without glucose. These findings suggest that supplementation of L-carnitine has a beneficial effect on the isolated heart under various conditions, and possibly on specific human heart diseases.     

Circular RNA YAP1 acts as the sponge of microRNA‐21‐5p to secure HK‐2 cells from ischaemia/reperfusion‐induced injury

Circular RNA YAP1 (circYAP1) was reported to participate in progression of gastric cancer. However, the role of circYAP1 in acute kidney injury (AKI) remains obscure. We attempted to examine the effects of circYAP1 on ischaemia/reperfusion‐stimulated renal injury. AKI model was established by treating HK‐2 cells in ischaemia/reperfusion (I/R) environment. CircYAP1 expression in blood of AKI patients and I/R‐treated HK‐2 cells was evaluated via RT‐qPCR. CCK‐8, flow cytometry, ELISA and ROS assay were executed to test the impact of circYAP1 on cell viability, apoptosis, inflammatory cytokines and ROS generation. Bioinformatic analysis was executed to explore miRNA targets. The relativity between circYAP1 and miR‐21‐5p was verified by RT‐qPCR and luciferase assay. The functions of miR‐21‐5p in I/R‐triggered injury were reassessed. PI3K/AKT/mTOR pathway was detected by Western blot. Down‐regulated circYAP1 was observed in AKI blood samples and I/R‐treated HK‐2 cells. CircYAP1 overexpression expedited cell growth and weakened secretion of inflammatory factors and ROS generation in I/R‐disposed cells. Besides, we found circYAP1 could sponge to miR‐21‐5p. Interestingly, miR‐21‐5p overexpression overturned the repressive effects of circYAP1 on cell injury. Moreover, PI3K/AKT/mTOR pathway was activated by circYAP1 via inhibiting miR‐21‐5p. We demonstrated that circYAP1 activated PI3K/AKT/mTOR pathway and secured HK‐2 cells from I/R injury via sponging miR‐21‐5p.     

Stable overexpression of DJ‐1 protects H9c2 cells against oxidative stress under a hypoxia condition

It has been well accepted that increased reactive oxygen species (ROS) and the subsequent oxidative stress is one of the major causes of ischemia/reperfusion (I/R) injury. DJ‐1 protein, as a multifunctional intracellular protein, plays an important role in regulating cell survival and antioxidant stress. Here, we wondered whether DJ‐1 overexpression attenuates simulated ischemia/reperfusion (sI/R)‐induced oxidative stress. A rat cDNA encoding DJ‐1 was inserted into a mammalian expression vector. After introduction of this construct into H9c2 myocytes, stable clones were obtained. Western blot analysis of the derived clones showed a 2.6‐fold increase in DJ‐1 protein expressing. Subsequently, the DJ‐1 gene‐transfected and control H9c2 cells were subjected to sI/R, and then cell viability, lactate dehydrogenase, malondialdehyde, intracellular ROS and antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) were measured appropriately. The results showed that stable overexpression of DJ‐1 efficiently attenuated sI/R‐induced viability loss and lactate dehydrogenase leakage. Additionally, stable overexpression of DJ‐1 inhibited sI/R‐induced the elevation of ROS and MDA contents followed by the increase of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) activities and expression. Our data indicate that overexpression of DJ‐1 attenuates ROS generation, enhances the cellular antioxidant capacity and prevents sI/R‐induced oxidative stress, revealing a novel mechanism of cardioprotection. Importantly, DJ‐1 overexpression may be an important part of a protective strategy against ischemia/reperfusion injury. Copyright © 2012 John Wiley & Sons, Ltd.     

ARRB1 ameliorates liver ischaemia/reperfusion injury via antagonizing TRAF6‐mediated Lysine 6‐linked polyubiquitination of ASK1 in hepatocytes

Hepatic ischaemia/reperfusion (I/R) injury is a major clinical problem during liver surgical procedures, which usually lead to early transplantation failure and higher organ rejection rate, and current effective therapeutic strategies are still limited. Therefore, in‐depth exploring of the molecular mechanisms underlying liver I/R injury is key to the development of new therapeutic methods. β‐arrestins are multifunctional proteins serving as important signalling scaffolds in numerous physiopathological processes, including liver‐specific diseases. However, the role and underlying mechanism of β‐arrestins in hepatic I/R injury remain largely unknown. Here, we showed that only ARRB1, but not ARRB2, was down‐regulated during liver I/R injury. Hepatocyte‐specific overexpression of ARRB1 significantly ameliorated liver damage, as demonstrated by decreases in serum aminotransferases, hepatocellular necrosis and apoptosis, infiltrating inflammatory cells and secretion of pro‐inflammatory cytokines relative to control mice, whereas experiments with ARRB1 knockout mice gotten opposite effects. Mechanistically, ARRB1 directly interacts with ASK1 in hepatocytes and inhibits its TRAF6‐mediated Lysine 6‐linked polyubiquitination, which then prevents the activation of ASK1 and its downstream signalling pathway during hepatic I/R injury. In addition, inhibition of ASK1 remarkably abolished the disruptive effect result from ARRB1 deficiency in liver I/R injury in vivo, indicating that ASK1 was required for ARRB1 function in hepatic I/R injury. In conclusion, we proposed that ARRB1 is a novel protective regulator during liver I/R injury, and modulation of the regulatory axis between ARRB1 and ASK1 could be a novel therapeutic strategy to prevent this pathological process.     

The protection by heme oxygenase‐1 induction against thioacetamide‐induced liver toxicity is associated with changes in arginine and asymmetric dimethylarginine

This study was designed to investigate the role of HO‐1 induction in prevention of thioacetamide (TAA)‐induced oxidative stress, inflammation and liver damage. The changes in hepatic dimethylarginine dimethylaminohydrolase (DDAH) activity as well as plasma arginine and asymmetric dimethylarginine (ADMA) levels were also measured to evaluate nitric oxide (NO) bioavailability. Rats were divided into four groups as control, hemin, TAA and hemin + TAA groups. Hemin (50 mg kg^?1, i.p.) was injected to rats 18 h before TAA treatment to induce HO‐1 enzyme expression. Rats were given TAA (300 mg kg^?1, i.p.) and killed 24 h after treatment. Although TAA treatment produced severe hepatic injury, upregulation of HO‐1 ameliorated TAA‐induced liver damage up to some extent as evidence by decreased serum alanine transaminase, aspartate transaminase and arginase activities and histopathological findings. Induction of HO‐1 stimulated antioxidant system and decreased lipid peroxidation in TAA‐treated rats. Myeloperoxidase activity and inducible NO synthase protein expression were decreased, whereas DDAH activity was increased by hemin injection in TAA‐treated rats. Induction of HO‐1 was associated with increased arginine levels and decreased ADMA levels, being the main determinants of NO production, in plasma of TAA‐treated rats. In conclusion, our results indicate that HO‐1 induction alleviated increased oxidative stress and inflammatory reactions together with deterioration in NO production in TAA‐induced liver damage in rats. Copyright © 2012 John Wiley & Sons, Ltd.     

Nobiletin attenuates acetaminophen‐induced hepatorenal toxicity in rats

The study aimed to examine the effects of nobiletin on the toxicity model induced with acetaminophen (APAP). For this purpose, 24 adult male rats were equally divided into four groups. The groups were the control group (group 1); dimethyl sulfoxide only, the APAP group (group 2) received a single dose of APAP 1000 mg/kg on the 10th day of experiment; the Nobiletin group (group 3), nobiletin (10 mg/kg) for 10 days; and the APAP + Nobiletin group (group 4), nobiletin (10 mg/kg) for 10 days with a single dose of APAP (1000 mg/kg) administered on the 10th day and the experiment ended after 48 hours. At the end of the study, a significant increase in malondialdehyde, interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6), and tumor necrosis factor‐α (TNF‐α) levels and a significant decrease in glutathione levels, glutathione peroxidase activities and nuclear factor erythroid‐derived 2‐like 2 (Nrf‐2) and heme oxygenase‐1 (HO‐1) expressions were observed with APAP application in liver and kidney tissues. Serum aspartate transaminase (AST), alanine transaminase (ALT), urea, and creatinine levels were also significantly increased in the APAP group. However, nobiletin treatment in group 4 reversed oxidative stress and inflammatory and histopathological signs caused by APAP. It is concluded that nobiletin may be a beneficial substance that confers hepatorenal protection to APAP‐induced toxicity via antioxidant and anti‐inflammatory mechanisms.     

Suppression of microRNA‐144‐3p attenuates oxygen–glucose deprivation/reoxygenation‐induced neuronal injury by promoting Brg1/Nrf2/ARE signaling

Accumulating evidence has reported that microRNA‐144‐3p (miR‐144‐3p) is highly related to oxidative stress and apoptosis. However, little is known regarding its role in cerebral ischemia/reperfusion‐induced neuronal injury. Herein, our results showed that miR‐144‐3p expression was significantly downregulated in neurons following oxygen–glucose deprivation and reoxygenation (OGD/R) treatment. Overexpression of miR‐144‐3p markedly reduced cell viability, promoted cell apoptosis, and increased oxidative stress in neurons with OGD/R treatment, whereas downregulation of miR‐144‐3p protected neurons against OGD/R‐induced injury. Brahma‐related gene 1 (Brg1) was identified as a potential target gene of miR‐144‐3p. Moreover, downregulation of miR‐144‐3p promoted the nuclear translocation of nuclear factor erythroid 2‐related factor 2 (Nrf2) and increased antioxidant response element (ARE) activity. However, knockdown of Brg1 significantly abrogated the neuroprotective effects of miR‐144‐3p downregulation. Overall, our results suggest that miR‐144‐3p contributes to OGD/R‐induced neuronal injury in vitro through negatively regulating Brg1/Nrf2/ARE signaling.     

IL—1受体拮抗剂减轻离体猪肾缺血／再灌注损伤的作用及其机制

目的研究IL-1受体拮抗剂(IL-1ra)对离体猪肾缺血/再灌注(IR)损伤的作用及机制。方法采用离体猪肾自体全血再灌注损伤模型,将32只猪肾随机分为对照组(n=11)、IR组(n=11)和IL-1ra组(n=10)。供肾猪均电击制动。对照组开腹后,即取肾下极作检测。IR组和IL-1ra组分别取再灌注2h尿及再灌注2.5h肾组织作检测。结果IR组肾皮质中MDA、TNF-α、IL-8含量高于对照组,而SOD、Na+-K+-ATP酶活力低于对照组,差异均具有显著性(P<0.01,以下同)。IL-1ra组肾皮质中MDA含量和SOD活力分别高于和低于对照组,差异均具有显著性;同IR组比较,IL-1ra组MDA、TNF-α、IL-8含量和尿量蛋白含量较低,SOD、Na+-K+-ATP酶活力较高。差异均具有显著性。IL-1ra组光、电镜下肾组织结构损伤较IR组轻。结论IL-1ra具有减轻离体猪肾IR损伤的作用。     

Effect of heme oxygenase‐1 transduced bone marrow mesenchymal stem cells on damaged intestinal epithelial cells in vitro

In this study, we explored the effects of mesenchymal stem cells (MSCs) from bone marrow overexpressing heme oxygenase‐1 (HO‐1) on the damaged human intestinal epithelial barrier in vitro. Rat MSCs were isolated from bone marrow and transduced with rat HO‐1 recombinant adenovirus (HO‐MSCs) for stable expression of HO‐1. Colorectal adenocarinoma 2 (Caco2) cells were treated with tumor necrosis factor‐α (TNF‐α) to establish a damaged colon epithelial model. Damaged Caco2 were cocultured with MSCs, Ad‐MSCs, Ad‐HO + MSCs or HO‐MSCs. mRNA and protein expression of Zona occludens‐1 (ZO‐1) and human HO‐1 and the release of cytokines were measured. ZO‐1 and human HO‐1 in Caco2 were significantly decreased after treatment with TNF‐α; and this effect was reduced when coculture with MSCs from bone marrow. Expression of ZO‐1 was not significantly affected by Caco2 treatment with TNF‐α, Ad‐HO, and MSCs. In contrast, ZO‐1 and human HO‐1 increased significantly when the damaged Caco2 was treated with HO‐MSCs. HO‐MSCs showed the strongest effect on the expression of ZO‐1 in colon epithelial cells. Coculture with HO‐MSCs showed the most significant effects on reducing the expression of IL‐2, IL‐6, IFN‐γ and increasing the expression of IL‐10. HO‐MSCs protected the intestinal epithelial barrier, in which endogenous HO‐1 was involved. HO‐MSCs play an important role in the repair process by reducing the release of inflammatory cytokines and increasing the release of anti‐inflammatory factors. These results suggested that HO‐MSCs from bone marrow were more effective in repairing the damaged intestinal epithelial barrier, and the effectiveness of MSCs was improved by HO‐1 gene transduction, which provides favorable support for the application of stem cell therapy in the intestinal diseases.