细胞色素C、凋亡蛋白酶3和凋亡蛋白酶8在大鼠双侧耳蜗切除后听皮层的表达

Expression of Cyt-C, Caspase 3, Caspase 8 in auditory cortex after bilateral cochlear ablation in rats

目的探索细胞色素C(cytochrome C,Cyt-C)、凋亡蛋白酶3(cysteinyl aspartate specificproteinase 3,Caspase 3)和凋亡蛋白酶8(cysteinylaspartate specific proteinase 8,Caspase 8)在大鼠听力剥夺后听皮层的表达。方法取SD大鼠48只,将其随机分为2、4、6、8周组和4个对照组,每组各6只。实验组动物行双侧耳蜗损毁术,取每组大鼠的双侧听皮层(n=12)用于免疫组织化学方法检测Cyt-C、Caspase 3和Caspase 8的表达。结果成功开展双侧耳蜗损毁术,Cyt-C免疫组化结果随时间呈上升趋势,方差分析显示实验组各组之间的差异均有统计学意义(P<0.05)。Caspase 3和Caspase 8的免疫组化结果显示,虽然表达量随时间呈上升趋势,但只在2～6周组间、2～8周组间、4～6周组间、4～8周组间、6～8周组间的差异有统计学意义(P<0.05)。结论听力剥夺导致听皮层神经元细胞的凋亡,凋亡速度在4周以前较慢,6周以后较快。

OBJECTIVE To research the expression of Cyt-C, Caspase 3 and Caspase 8 in auditory cortex after bilateral cochlear ablation in rats. METHODS 48 SD rats were randomly divided into 2-week group, 4-week group, 6-week group, 8-week group and 4 corresponding control groups （CG） with 6 rats （n=12） in each group. Bilateral cochlear ablation was done in experiment groups and then immunohistochemical detection was adopted for Cyt-C, Caspase 3 and Caspase 8 in bilateral auditory cortex of each group. RESULTS The model of auditory deprivation on rat was successfully established. The expression of Cyt-C increased by time, with statistical differences （P〈0.05） between any two traumatized groups. The expression of Caspase 3 and Caspase 8 increased by time too, but with statistical differences （P〈0.05） only between 2-week and 6-week, 2-week and 8-week, 4-week and 6-week, 4-week and 8-week, 6-week and 8-week. CONCLUSION The speed of neuronal apoptosis in auditory cortex caused by bilateral cochlear ablation was slow before 4 weeks and fast after 6 weeks.