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Ephrin-B2 has been shown to participate in angiogenesis, but the underlying mechanisms involved remain unclear. In this study, a rat model of local cerebral ischemia was prepared by focal middle cerebral artery occlusion, followed by 24-hour reperfusion. Then, ephrin-B2 protein was administered intracerebroventricularly for 3 consecutive days via a micro-osmotic pump. Western blot assay and quantitative real-time reverse transcription PCR demonstrated the expression levels of angiopoietin-1 （Ang-1） mRNA and protein in the penumbra cortex of the ephrin-B2 treated group were decreased at day 4 after reperfusion, and increased at day 28, while the expression levels of angiopoietin-2 （Ang-2） were highly up-regulated at all time points tested. Double immunofluorescent staining indicated that Ang-1 and Ang-2 were both expressed in vascular endothelial cells positive for CD31. These findings indicate that ephrin-B2 influences the expressions of Ang-1 and Ang-2 during angiogenesis following transient focal cerebral ischemia.

Signal transducer and activator of transcription（STAT）is a unique protein family that binds to DNA,coupled with tyrosine phosphorylation signaling pathways,acting as a transcriptional regulator to mediate a variety of biological effects.Cerebral ischemia and reperfusion can activate STATs signaling pathway,but no studies have confirmed whether STAT activation can be verified by diffusion-weighted magnetic resonance imaging（DWI）in rats after cerebral ischemia/reperfusion.Here,we established a rat model of focal cerebral ischemia injury using the modified Longa method.DWI revealed hyperintensity in parts of the left hemisphere before reperfusion and a low apparent diffusion coefficient.STAT3 protein expression showed no significant change after reperfusion,but phosphorylated STAT3 expression began to increase after 30 minutes of reperfusion and peaked at 24 hours.Pearson correlation analysis showed that STAT3 activation was correlated positively with the relative apparent diffusion coefficient and negatively with the DWI abnormal signal area.These results indicate that DWI is a reliable representation of the infarct area and reflects STAT phosphorylation in rat brain following focal cerebral ischemia/reperfusion.

Penehyclidine hydrochloride can promote microcirculation and reduce vascular permeability. However, the role of penehyclidine hydrochlodde in cerebral ischemia-reperfusion injury remains unclear. In this study, in vivo middle cerebral artery occlusion models were established in experimental rats, and penehyclidine hydrochloride pretreatment was given via intravenous injection prior to model establishment. Tetrazolium chloride, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling and immunohistochemical staining showed that, penehyclidine hydrochloride pretreatment markedly attenuated neuronal histopathological changes in the cortex, hippocampus and striatum, reduced infarction size, increased the expression level of BcI-2, decreased the expression level of caspase-3, and inhibited neuronal apoptosis in rats with cerebral ischemia-reperfusion injury. Xanthine oxidase and thiobarbituric acid chromogenic results showed that penehyclidine hydrochloride upregulated the activity of superoxide dismutase and downregulated the concentration of malondialdehyde in the ischemic cerebral cortex and hippocampus, as well as reduced the concentration of extracellular excitatory amino acids in rats with cerebral ischemia-reperfusion injury. In addition, penehyclidine hydrochloride inhibited the expression level of the NR1 subunit in hippocampal nerve cells in vitro following oxygen-glucose deprivation, as detected by PCR. Experimental findings indicate that penehyclidine hydrochloride attenuates neuronal apoptosis and oxidative stress injury after focal cerebral ischemia-reperfusion, thus exerting a neuroprotective effect.

Pretreatment with scutellaria baicalensis stem-leaf total flavonoid has protective effects against ischemia and attenuates myocardial ischemia-reperfusion injury. In this study, rats were given scutellaria baicalensis stem-leaf total flavonoid intragastrically at 50, 100, and 200 mg/kg per day for 7 days before focal cerebral ischemia-reperfusion injury models were established using the suture method. We then determined the protective effects of scutellaria baicalensis stem-leaf total flavon- oid pretreatment on focal cerebral ischemia-reperfusion injury. Results showed that neurological deficit scores increased, infarct volumes enlarged, apoptosis increased and Bcl-2 and Bax protein expression were upregulated at 24 hours after reperfusion. Pretreatment with scutellaria baicalensis stem-leaf total flavonoid at any dose lowered the neurological deficit scores, reduced the infarct volume, prevented apoptosis in hippocampal cells, attenuated neuronal and blood-brain barrier damage and upregulated Bcl-2 protein expression but inhibited Bax protein expression. Doses of 100 and 200 mg/kg were the most efficacious. Our findings indicate that pretreatment with scutel- laria baicalensis stem-leaf total flavonoid at 100 and 200 mg/kg can improve the neurological func- tions and have preventive and protective roles after focal cerebral ischemia-reperfusion injury.

目的 观察纳洛酮对大鼠局灶性脑缺血再灌注损伤的保护作用。方法 用改良Longa法制作局灶性脑缺血再灌注损伤模型，观察不同剂量纳洛酮对模型大鼠神经功能障碍、脑梗死范围、脑组织病理改变以及血清中乳酸脱氢酶(LDH)和肌酸激酶(CK)含量的影响。结果 纳洛酮能剂量依赖性地降低模型大鼠的血清LDH、CK，减少梗死面积。降低神经功能行为评分，减轻脑组织病理改变。结论 纳洛酮对大鼠局灶性脑缺血再灌注损伤有一定的保护作用。