Correlation between expression of two transforming growth factor-beta 1 receptors and microvascular density in a rat model of cerebral ischemia and reperfusion injury

The effects of transforming growth factor-β1 （TGF-β1） are currently controversial. Whether TGF-β1 promotes or inhibits revascularization under different conditions remains poorly understood. Based on previous studies, the current experiment established rat models of cerebral ischemia and reperfusion injury （IRI）, and demonstrated that pathological and functional damage was also increased after IRI. The most serious damage was observed at 3 days after reperfusion, at which time microvascular density fell to its lowest level. Soon afterwards, microvascular density increased, new collateral circulation was gradually established at 4 to 7 days after reperfusion, and pathological damage and neurological deficits were improved. TGF-β1, activin receptor-like kinase 5 （ALK5） mRNA and protein expression levels increased gradually over time. In contrast, ALK1 mRNA and protein expression decreased over the same period. A significant negative correlation was detected between microvascular density and expression of the ALK5 gene transcript. There was no correlation between microvascular density and ALK1 gene transcriptional expression following cerebral IRI in a rat model. These findings suggest that ALK5, rather than ALK1, is the critical receptor in the TGF-β1 signal pathways after cerebral IRI.

MicroRNA-670 aggravates cerebral ischemia/reperfusion injury via the Yap pathway

Apoptosis is an important programmed cell death process involved in ischemia/reperfusion injury.MicroRNAs are considered to play an important role in the molecular mechanism underlying the regulation of cerebral ischemia and reperfusion injury.However,whether miR-670 can regulate cell growth and death in cerebral ischemia/reperfusion and the underlying mechanism are poorly understood.In this study,we established mouse models of transient middle artery occlusion and Neuro 2a cell models of oxygen-glucose deprivation and reoxygenation to investigate the potential molecular mechanism by which miR-670 exhibits its effects during cerebral ischemia/reperfusion injury both in vitro and in vivo.Our results showed that after ischemia/reperfusion injury,miR-670 expression was obviously increased.After miR-670 expression was inhibited with an miR-670 antagomir,cerebral ischemia/reperfusion injury-induced neuronal death was obviously reduced.When miR-670 overexpression was induced by an miR-670 agomir,neuronal apoptosis was increased.In addition,we also found that miR-670 could promote Yap degradation via phosphorylation and worsen neuronal apoptosis and neurological deficits.Inhibition of miR-670 reduced neurological impairments after cerebral ischemia/reperfusion injury.These results suggest that microRNA-670 aggravates cerebral ischemia/reperfusion injury through the Yap pathway,which may be a potential target for treatment of cerebral ischemia/reperfusion injury.The present study was approved by the Institutional Animal Care and Use Committee of China Medical University on February 27,2017(IRB No.2017PS035K).

Protective effects of combination of Xuesaitong and aspirin on cerebral ischemia and reperfusion injury in rats

Objective：To investigate the protective effects of the combination of Xuesaitong（XST）and aspirin on cerebral ischemia and reperfusion injury（CIRI）in rats,and further explore the underlying mechanisms.Methods：A total of 150 male Sprague-Dawley（SD）rats were randomly divided into five groups with 30rats in each group：sham group,middle cerebral artery occlusion/reperfusion（MCAO/R）model group,XST group,aspirin group,and XST＋aspirin group.Rats were pretreated with XST,aspirin,or XST＋aspirin for7 d.One hour after the last administration,a model of CIRI was induced by MCAO/R.Neurological deficits were assessed using Longa’s five-point scale.Cerebral edema was detected by the measurement of brain water content.The volume of cerebral infarction was determined by 2,3,5-triphenyltetrazolium chloride（TTC）staining.The activities of superoxide dismutase（SOD）,catalase（CAT）,and glutathione peroxidase（GSH-Px）,as well as levels of malonaldehyde（MDA）were detected by commercial kits.Enzyme-linked immunosorbent assay（ELISA）was used to determine the levels of interleukin-1（）,interleukin-4（IL-4）,interleukin-6（IL-6）,interleukin-10（IL-10）,tumor necrosis factor-alphamonocyte chemotactic protein 1（MCP-1）,and kynurenine in serum,cerebral cortex,and hippocampus of MCAO/R rats.The protein expression of nuclear factor erythroid 2-related factor（Nrf2）,heme oxygenase-1（HO-1）,I-kappa B alpha（IκBα）,and nuclear factor kappa B（B）/p65 in the cortex were analyzed by western blotting.Results：Treatment of XST,aspirin,and XST＋aspirin significantly alleviated the neurological deficits,cerebral edema,and cerebral infarct volume induced by MCAO/R.Treatment of XST,aspirin,and XST＋aspirin also reduced MDA,,MCP-1,and kynurenine levels,and increased SOD,CAT,GSH-Px,IL-4,and IL-10 levels in serum,cerebral cortex,and hippocampus of MCAO/R rats.Furthermore,treatment of XST,aspirin,and XST＋aspirin decreased the expression of nuclearB/p65 and increased the expression of IκBα,nuclear Nrf2,and HO-1.Importantly,the combination of XST and aspirin enhanced the protective effects of XST or aspirin treatment alone on CIRI in rats.Conclusion：The combination of XST and aspirin significantly inhibited oxidative stress and inflammation in serum,cerebral cortex,and hippocampus of MCAO/R rats.The combination of XST and aspirin exerted more protective effects than XST or aspirin treatment alone.The combination of XST and aspirin might provide the synergistic therapeutic effects on CIRI,and deserve further clinical investigation.