Several studies have reported that microRNA (MIR) is involved in the pathogenesis and progression of ischemic diseases, including cerebral ischemia, and that MIR-22 may inhibit the inflammatory response and cell apoptosis, which contribute to ischemia/reperfusion (I/R) injury. However, the specific function of MIR-22 in cerebral I/R injury remains far from clear. This study aimed to examine the potential protective effect of MIR-22 against cerebral I/R injury and its mechanism. As predicted, adenovirus-mediated MIR-22 overexpression markedly reduced the neurological score and infarct size (P < 0.05). We demonstrated that MIR-22 overexpression resulted in a reduction in inflammatory cytokines TNF-α, IL-6, COX-2, and iNOS, whereas the level of IL-10 was enhanced. MIR-22 overexpression significantly inhibited NF-κB activity by decreasing NF-κB coactivator NCOA1 expression. Furthermore, we found that MIR-22 could reduce the apoptotic rate of cortical neurons. Caspase-3 activity was inhibited by MIR-22, and the expression of the anti-apoptosis gene Bcl-2 in neurons was increased and that of the pro-apoptosis gene Bax decreased following MIR-22 overexpression. Our results suggest that MIR-22 could be used to treat cerebral I/R injury and that its neuroprotective effect may be attributed to a reduction in inflammation and apoptosis.
Background. Endogenous cannabinoid anandamide (AEA) protects neurons from oxidative injury in rodent models; however the mechanism of AEA-induced neuroprotection remains to be determined. Activation of neuronal NADPH oxidase 2 (Nox2) contributes to oxidative damage of the brain, and inhibition of Nox2 can attenuate cerebral oxidative stress. We aimed to determine whether the neuronal Nox2 was involved in protection mediated by AEA. Methods. The mouse hippocampal neuron cell line HT22 was exposed to hydrogen peroxide (H2O2) to mimic oxidative injury of neurons. The protective effect of AEA was assessed by measuring cell metabolic activity, apoptosis, lactate dehydrogenase (LDH) release, cellular morphology, intracellular reactive oxygen species (ROS), and antioxidant and oxidant levels and Nox2 expression. Results. HT22 cells exposed to H2O2 demonstrated morphological changes, decreased LDH release, reduced metabolic activity, increased levels of intracellular ROS and oxidized glutathione (GSSG), reduced levels of superoxide dismutase (SOD), and reduced glutathione (GSH) and increased expression of Nox2. AEA prevented these effects, a property abolished by simultaneous administration of CB1 antagonist AM251 or CB1-siRNA. Conclusion. Nox2 inhibition is involved in AEA-induced cytoprotection against oxidative stress through CB1 activation in HT22 cells.
Etomidate plus propofol had few effects on respiration and circulation in patients undergoing gastroscopy and was more safe and effective than propofol alone.
Brief isoflurane anesthesia induces ischemic tolerance in the brain. The effect was found to be dose dependent in a rat focal cerebral ischemia model. Ischemic tolerance induced by isoflurane preconditioning is dependent on activation of adenosine triphosphate-regulated potassium channels.
Background. Cytoprotectant amifostine attenuates radiation-induced oxidative injury by increasing intracellular manganese superoxide dismutase (SOD2) in peripheral tissue. However, whether amifostine could protect neuronal cells against oxidative injury has not been reported. The purpose of this study is to explore the protection of amifostine in PC12 cells. Methods. PC12 cells exposed to glutamate were used to mimic neuronal oxidative injury. SOD assay kit was taken to evaluate intracellular Cu/Zn SOD (SOD1) and SOD2 activities; western blot analysis and immunofluorescence staining were performed to investigate SOD2 protein expression; MTT, lactate dehydrogenase (LDH), release and cell morphology were used to evaluate cell injury degree, and apoptotic rate and cleaved caspase-3 expression were taken to assess apoptosis; mitochondrial superoxide production, intracellular reactive oxygen species (ROS), and glutathione (GSH) and catalase (CAT) levels were evaluated by reagent kits. Results. Amifostine increased SOD2 activity and expression, decreased cell injury and apoptosis, reduced mitochondrial superoxide production and intracellular ROS generation, and restored intracellular GSH and CAT levels in PC12 cells exposed to glutamate. SOD2-siRNA, however, significantly reversed the amifostine-induced cytoprotective and antioxidative actions. Conclusion. SOD2 mediates amifostine-induced protection in PC12 cells exposed to glutamate.
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