人尿激肽原酶对急性局灶性脑缺血再灌注损伤大鼠细胞凋亡的影响

Effects of human urinary kallikrein on cell apoptosis of rats with acute focal cerebral ischemia- reperfnsion injury

目的研究人尿激肽原酶（HUK）对大鼠急性局灶性脑缺血再灌注（FCIR）损伤后细胞凋亡数量及B细胞淋巴瘤／白血病-2（Bcl-2）、Bcl-2联合X蛋白（Bax）蛋白表达的影响。方法84只雄性SD大鼠分为假手术组（12只）、脑缺血再灌注（IR）组（36只）、HUK处理组（36只），IR组和HUK处理组剩余大鼠又按照再灌注时间6h、12h、24h、72h、168h分为5个亚组（均为6只）。建立大鼠大脑中动脉FCIR模型。假手术组、IR组及HUK处理组中各取6只SD大鼠用于测定梗死体积，其余大鼠用于观察神经功能缺陷评分、TUNEL法及免疫组化检测凋亡细胞数量及凋亡蛋白Bcl-2、Bax的表达。结果HUK处理组神经功能缺陷评分、梗死灶体积、除168h亚组外的各时间点的凋亡细胞数及Bax蛋白表达均显著少于IR组（P〈0．05），除168h亚组外的各时间点的Bcl-2蛋白表达均显著高于瓜组（P〈0．05）。结论HUK对FCIR后的脑组织起保护作用，其机制可能为损伤后3d内通过上调Bcl-2、下调Bax蛋白表达来抑制细胞凋亡。

Objective To study the effects of human urinary kallikrein （HUK） on the number of apoptotic cells and the expressions of Bcl-2 and Bax proteins in rats after focal cerebral iscbemia and reperfusion （FCIR） injury. Methods Eighty-four Spraque-Dawley （SD） male rats were randomly divided into sham-operated group （n=12）, iscbemia-reperfusion group （n=36）, and HUK-treated group （n=36）. Transient focal cerebral iscbemia models were established by middle cerebral artery occlusion. Six rats were chosen from sham-operated group, iscbemia-reperfusion group, and HUK-treated group for measuring infarct sizes. The rest were used to evaluate neurologic function impairment and measure the number of apoptotic cells and Bcl-2 or Bax protein positive cells in cerebral cortex with TUNEL and immunohistochemistry. The latter 2 groups were subdivided into 6, 12, 24, 72, 168 h reperfusion groups （each n=6）. Results The neurologic function impairment score, the infarct sizes, the apoptotic cells and the expression of Bax protein of HUK-treated group at different time points （except 168 h group） significantly decreased compared with those ofischemia-reperfusion group （P〈0.05）. The expression of Bcl-2 protein of HUK-treated group at different time points （except 168 h group） remarkably increased compared with that of ischemia-reperfusion group （P〈0.05）. Conclusions HUK can exert a protection against FCIR injury, maybe through up-regulating Bcl-2 and down-regulating Bax protein in the initial 3 d of FCIR injury to decrease the number of apoptotic cells