E64d对创伤性脑损伤小鼠神经细胞的保护作用

Neuronal Cell Protection by E64d after Traumatic Brain Injury in Mice

目的探讨组织蛋白酶B和μ-钙激活蛋白酶的特异性抑制剂E64d对创伤性脑损伤(TBI)后神经细胞的保护作用,并对其调节机制进行初步探讨,为临床救治TBI患者提供新的靶点。方法采用改良的自由落体损伤装置建立小鼠TBI模型,实验组侧脑室注射0.5μg/μl的E64d 1μl,对照组侧脑室注射等体积1%的二甲基亚砜,并按伤后时间不同分为伤后1 h、6 h、12 h、24 h、48 h组,并按时间点断头取脑,运用Western blot法检测TBI后各实验组脑组织中凋亡相关蛋白caspase-3、tBid的表达情况,运用免疫荧光法进行caspase-3阳性细胞计数。结果实验组凋亡相关蛋白caspase-3、tBid的表达量明显降低,且以伤后24～48 h最为显著(P<0.05)。结论 E64d可以通过阻断内外源的凋亡通路对TBI后神经细胞起保护作用,改善神经细胞损伤导致的神经功能障碍,可能为治疗脑外伤提供新靶点,为研究防治创伤性脑损伤后继发性损伤提供新思路。

Objective To investigate the effects of E64d（a cathepsin B and μ-calpain inhibitor） on TBI induced neuronal cell death.Methods The TBI model was established by weight drop device in adult mice based on procedures previously reported.One hundred mature male mice were randomly divided into the DMSO（1μl）-treated control group and E64d（0.5μg/μl） treated group based on time course of TBI.Animals were sacrificed at 1 h,6 h,12 h,24 h,and 48 h time point after suffering TBI.The brain tissues were undergone immunofluorescence or Western blot analysis for caspase-3 activity,tBid,lysosomal enzyme cathepsin B.Results E64d pretreatment drastically reduced TBI induced caspase-3 activation and tBid protein levels in the injured cortex and hippocampus（P0.05）.Conclusion Lateral cerebral ventricle administration of cathepsin B and μ-calpain inhibitor E64d could significantly attenuate the TBI-induced neuronal cell death and dysfunction.