microRNA-455-5p alleviates neuroinflammation in cerebral ischemia/reperfusion injury

Neuroinflammation is a major pathophysiological factor that results in the development of brain injury after cerebral ischemia/reperfusion.Downregulation of microRNA(miR)-455-5p after ischemic stroke has been considered a potential biomarker and therapeutic target for neuronal injury after ischemia.However,the role of miR-455-5p in the post-ischemia/reperfusion inflammatory response and the underlying mechanism have not been evaluated.In this study,mouse models of cerebral ischemia/reperfusion injury were established by transient occlusion of the middle cerebral artery for 1 hour followed by reperfusion.Agomir-455-5p,antagomir-455-5p,and their negative controls were injected intracerebroventricularly 2 hours before or 0 and 1 hour after middle cerebral artery occlusion(MCAO).The results showed that cerebral ischemia/reperfusion decreased miR-455-5p expression in the brain tissue and the peripheral blood.Agomir-455-5p pretreatment increased miR-455-5p expression in the brain tissue,reduced the cerebral infarct volume,and improved neurological function.Furthermore,primary cultured microglia were exposed to oxygen-glucose deprivation for 3 hours followed by 21 hours of reoxygenation to mimic cerebral ischemia/reperfusion.miR-455-5p reduced C-C chemokine receptor type 5 mRNA and protein levels,inhibited microglia activation,and reduced the production of the inflammatory factors tumor necrosis factor-αand interleukin-1β.These results suggest that miR-455-5p is a potential biomarker and therapeutic target for the treatment of cerebral ischemia/reperfusion injury and that it alleviates cerebral ischemia/reperfusion injury by inhibiting C-C chemokine receptor type 5 expression and reducing the neuroinflammatory response.

Rac1 relieves neuronal injury induced by oxygen-glucose deprivation and re-oxygenation via regulation of mitochondrial biogenesis and function

Certain microRNAs(miRNAs)can function as neuroprotective factors after reperfusion/ischemia brain injury.miRNA-142-3p can participate in the occurrence and development of tumors and myocardial ischemic injury by negatively regulating the activity of Rac1,but it remains unclear whether miRNA-142-3p also participates in cerebral ischemia/reperfusion injury.In this study,a model of oxygen-glucose deprivation/re-oxygenation in primary cortical neurons was established and the neurons were transfected with miR-142-3p agomirs or miR-142-3p antagomirs.miR-142-3p expression was down-regulated in neurons when exposed to oxygen-glucose deprivation/re-oxygenation.Over-expression of miR-142-3p using its agomir remarkably promoted cell death and apoptosis induced by oxygen-glucose deprivation/re-oxygenation and improved mitochondrial biogenesis and function,including the expression of peroxisome proliferator-activated receptor-γcoactivator-1α,mitochondrial transcription factor A,and nuclear respiratory factor 1.However,the opposite effects were produced if miR-142-3p was inhibited.Luciferase reporter assays verified that Rac Family Small GTPase 1(Rac1)was a target gene of miR-142-3p.Over-expressed miR-142-3p inhibited NOX2 activity and expression of Rac1 and Rac1-GTPase(its activated form).miR-142-3p antagomirs had opposite effects after oxygen-glucose deprivation/re-oxygenation.Our results indicate that miR-142-3p down-regulates the expression and activation of Rac1,regulates mitochondrial biogenesis and function,and inhibits oxygen-glucose deprivation damage,thus exerting a neuroprotective effect.The experiments were approved by the Committee of Experimental Animal Use and Care of Central South University,China(approval No.201703346)on March 7,2017.

Effects of Compound Shenhua Tablet(复方肾华片) on Renal Tubular Na^+-K^+-ATPase in Rats with Acute Ischemic Reperfusion Injury

Objective： To observe the effect of Compound Shenhua Tablet （复方肾华片, SHT） on the sodium- potassium-exchanging adenosinetriphosphatase （Na＋-K＋-ATPase） in the renal tubular epithelial cells of rats with acute ischemic reperfusion and to investigate the mechanisms underlying the effects of SHT on renal ischemic reperfusion injury （RIRI）. Methods： Fifty male Wistar rats were randomly divided into the sham surgery group, model group, astragaloside group [150 mg/（kg.d）], SHT low-dose group [1.5 g/（kg,d）] and SHT high-dose group [3.0 g/（kg.d）], with 10 rats in each group. After 1 week of continuous intragastric drug administration, surgery was performed to establish the model. At either 24 or 72 h after the surgery, 5 rats in each group were sacrificed, blood biochemistry, renal pathology, immunoblot and immunohistochemical examinations were performed, and double immunofluorescence staining was observed under a laser confocal microscope. Results： Compared with the sham surgery group, the serum creatinine （SCr） and blood urea nitrogen （BUN） levels were significantly increased, Na＋-K＋-ATPase protein level was decreased, and kidney injury molecule-1 （KIM-1） protein level was increased in the model group after the surgery （P〈0.01 or P〈0.05）. Compared with the model group, the SCr, BUN, pathological scores, Na＋-K＋-ATPase, and the KIM-1 protein level of the three treatment groups were significantly improved at 72 h after the surgery （P〈0.05 or P〈0.01）. And the SCr, BUN of the SHT low- and high-dose groups, and the pathological scores of the SHT high-dose group were significantly lower than those of the astragaloside group （P〈0.05）. The Iocalizations of Na＋-K＋-ATPase and megalin of the model group were disrupted, with the distribution areas overlapping with each other and alternately arranged. The severity of the disruption was slightly milder in three treatment groups compared with that of the model group. The results of immunofluorescence staining showed that the SHT high-dose group had a superior effect as compared with the astragaloside group and the SHT low-dose group. Conclusions： The SHT effectively alleviated RIRI caused by ischemic reperfusion, promoted the recovery of the polarity of renal tubular epithelial cells, and protected the renal tubules. The therapeutic effects of SHT were superior to those of astragaloside as a single agent.

Exosomal transfer of microRNA-590-3p between renal tubular epithelial cells after renal ischemia-reperfusion injury regulates autophagy by targeting TRAF6

Background:Acute kidney injury(AKI)is a common complication in patients,especially elderly patients,who undergo cardiac surgery with cardiopulmonary bypass.Studies have indicated a protective role of autophagy in AKI.However,the mechanisms underlying the regulatory effect of autophagy in AKI among patients undergoing cardiac surgeries are poorly understood.In this study,we aimed to test the hypothesis that exosomal microRNAs(miRNAs)regulate autophagy in tubular epithelial cells after AKI.Methods:Plasma exosomal RNA was extracted from young and elderly AKI patients undergoing cardiac surgery,and the miRNAs expression during the perioperative period were analyzed using next-generation sequencing.The screened miRNAs and their target genes were subjected to gene oncology function and Kyoto Encyclopedia of Genes and Genome enrichment analyses.Renal tubular epithelial cell line(HK-2 cells)was cultured and hypoxia/reoxygenation(H/R)model was established,which is an in vitro renal ischemia/reperfusion(I/R)model.We used Western blot analysis,cell viability assay,transfection,luciferase assay to investigate the mechanisms underlying the observed increases in the levels of renal I/R injury-mediated exosomal miRNAs and their roles in regulating HK-2 cells autophagy.Results:miR-590-3p was highly enriched in the plasma exosomes of young AKI patients after cardiac surgery.Increased levels of miR-590-3p led to the increases in the expression of autophagy marker proteins,including Beclin-1 and microtubule associated protein 1 light chain 3 beta(LC3II),and prolonged the autophagic response in HK-2 cells after H/R treatment.These effects were achieved mainly via increases in the exosomal miR-590-3p levels,and the tumor necrosis factor receptor-associated factor 6 protein was shown to play a key role in I/R injury-mediated autophagy induction.Conclusion:Exosomes released from HK-2 cells after renal I/R injury regulate autophagy by transferring miR-590-3p in a paracrine manner,which suggests that increasing the miR-590-3p levels in HK-2 cell-derived exosomes may increase autophagy and protect against kidney injury after renal I/R injury.

缺血后适应研究进展

心肌缺血再灌注损伤是心脏科医师经常面对的问题,目前对其治疗仍然苍白无力,近来研究发现,在冠状动脉再灌注开始时对冠脉进行几轮短暂、重复的再灌注/闭塞过程,随后恢复冠脉血流,即“缺血后适应”,可明显保护心脏,减轻缺血再灌注损伤,并为心肌梗死的再灌注治疗提供了一条新途径。

热休克应答对大鼠脑缺血再灌注后神经细胞凋亡的影响

目的:研究热休克应答对大鼠脑缺血再灌注后神经细胞凋亡的影响,探索热休克蛋白70治疗缺血性再灌注损伤的应用前景。方法:将46只成年Wistar大鼠随机分为假手术组、对照组与试验组。除假手术组大鼠外,其余大鼠均制作全脑缺血再灌注动物模型,对照组不进行热休克应答干预,试验组在全脑缺血再灌注后进行热休克干预,即静脉注射热休克蛋白70,分别于不同时间段(6小时、12小时)检测各组大鼠脑神经细胞凋亡数目,对比分析各组大鼠神经细胞凋亡情况的差异,验证热休克蛋白70对大鼠脑缺血再灌注后神经细胞凋亡的保护作用。结果:与对照组比较,试验组大鼠脑神经细胞凋亡数目减少,差异有统计学意义(P<0.05)。结论:热休克应答对大鼠脑缺血再灌注后神经细胞凋亡有保护性作用,热休克蛋白70对缺血性脑血管病再灌注损伤有一定的治疗前景。

缺血后适应脑保护机制的研究进展

如今延长溶栓时间窗、减轻再灌注损伤是缺血性脑血管病亟待解决的的问题,缺血后适应提供了一种可能的解决方法,故成为研究的热点。缺血后适应通常指的是在组织缺血-再灌注之后进行的一系列短暂血管闭塞/血管再灌注,诱导组织针对缺血-再灌注损伤产生内源性保护作用,减少组织器官缺血-再灌注损伤。该文将综述缺血后适应脑保护的基本机制:减少缺血-再灌注后脑血流的改变,减少氧化应激产物的产生,抗炎,相关信号传导通路改变。

Protective effect of Xuebijing injection on myocardial injury in patients with sepsis: a randomized clinical trial

OBJECTIVE: To investigate the protective effect and possible mechanism of Xuebijing Injection on myocardial injury in patients with sepsis, and to evaluate its prognostic implications.METHODS: Patients with septic myocardial injury were recruited, and were randomly divided into two groups: treatment group and control group. All patients in two groups received conventional cluster treatment, the patients in treatment group additional received Xuebijing injection dissolved in0.9% sodium chloride injection, and the patients in control group received the same amount of 0.9%sodium chloride injection. At the beginning of treatment and 3, 7 and 10-day after treatment, lab-oratory indicators of cardiac troponin Ⅰ(cTnI),N-terminal pro B-type natriuretic peptide(NT-pro BNP) and procalcitonin(PCT) were respectively tested in venous blood. The patient's length of stay in Intensive Care Unit(ICU) and the mortality in 28 days were recorded.RESULTS: At 3, 7 and 10-day after treatment, the improvements of c Tn I, NT-pro BNP and PCT in treatment group were better than those in control group, and the differences were statistically significant(P < 0.05). The mortality of treatment group in28 days was not significantly different from that of control group(P > 0.05). The ICU length of stay of treatment group was shorter than that of control group(P > 0.05).CONCLUSION: Xuebijing injection could improve the levels of c Tn I, NT-pro BNP and PCT in patients with septic myocardial injury.and it had a protective effect on myocardial injury.