乳化异氟醚预处理对大鼠局灶性脑缺血再灌注时脑组织突触后致密物质95活化的影响

目的 探讨乳化异氟醚预处理对大鼠局灶性脑缺血再灌注时脑组织突触后致密物质95(PSD95)活化的影响.方法 雄性清洁级SD大鼠32只,体重280 ～ 300 g,采用随机数字表法,将大鼠随机分为4组(n=8):假手术组(S组)、缺血再灌注组(I/R组)、乳化异氟醚组(EI组)和脂肪乳剂组(LE组).采用大脑中动脉阻塞法制备局灶性脑缺血再灌注模型.EI组和LE组分别腹腔注射8％乳化异氟醚10.5 ml/mg或30％脂肪乳10.5 ml/mg,24h后制备模型.再灌注6h时行神经功能缺陷评分,随机取4只大鼠,处死后取缺血侧海马和皮层组织,采用Western blot法检测磷酸化的PSD95( pPSD95)的表达水平.再灌注24 h时,随机取4只大鼠,处死后取脑组织,计算脑梗死体积百分比.结果 S组未见神经功能缺陷和脑梗死发生.与S组比较,I/R组、EI组和LE组神经功能缺陷评分、脑梗死体积百分比、海马和皮质pPSD95表达水平升高(P＜0.01)；与I/R组比较,EI组神经功能缺陷评分、脑梗死体积百分比、海马和皮质pPSD95表达水平降低(P＜0.05),LE组差异无统计学意义(P＞0.05).结论乳化异氟醚可通过抑制脑组织PSD95的活化,减轻大鼠局灶性脑缺血再灌注损伤.

Effect of emulsified isoflurane preconditioning on postsynaptic density protein 95 activation in brain during focal cerebral ischemia-reperfusion injury in rats

Objective To investigate the effect of emulsified isoflurane preconditioning on postsynaptic density protein 95 (PSD95) activation in brain during focal cerebral ischemia-reperfusion (I/R)injury in rats.Methods Thirty-two pathogen-free male SD rats weighing 280-300 g were randomly divided into 4 groups (n =8each): sham operation group(group S),group I/R,emulsified isoflurane group(group EI) and lipid emulsion group(group LE).Focal cerebral I/R was induced by middle cerebral artery occlusion for 2 h followed by reperfusion.8％ emulsified isoflurane 10.5 ml/mg or 30％ lipid emulsion 10.5 ml/mg was injected intraperitoneally at 24h before I/R in groups EI and LE respectively.The neurologic deficit score (NDS) was evaluated at 6 h of reperfusion and then 4 rats were sacrificed,and brains were removed for determination of phosphorylatied PSD95 (pPSD95) expression in ischemia cortex and hippocampus by Western blot.Four rats were sacrificed at 24 h of reperfusion and then their brains were removed for determination of infarct volume percentage.Results NDS,infarct volume percentage and pPSD95 expression in ischemia cortex and hippocampus were higher in groups I/R,EI and LE than in group S( P ＜ 0.01 ).NDS,infarct volume percentage and pPSD95 expression in ischemia cortex and hippocampus were lower in group EI than in group I/R( P ＜ 0.05).There was no significant difference in NDS,infarct volume percentage and pPSD95 expression between groups I/R and LE(P ＞ 0.05).Conclusion Emulsified isoflurane preconditioning can attenuate focal cerebral I/R injury in rats by inhibiting PSD95 activation in brain.