缺氧缺血性脑损伤新生大鼠脑神经细胞凋亡及脑组织中Rho GDP解离抑制因子和Bcl-2表达的变化

目的 研究Rho GDP解离抑制因子(Rho GDP dissociation inhibitor 2,RhoGDI2)mRNA 及Bcl-2 mRNA的表达在缺氧缺血性脑损伤(hypoxic-ischemic brain damage,HIBD)中的作用和机制.方法 30只新生7日龄SD大鼠按照完全随机化方法分为假手术组及HIBD 6 h和48 h组,每组10只.采用流式细胞仪检测脑细胞凋亡情况,并用Real-time RT-PCR方法测定脑组织中RhoGDI2和Bcl-2mRNA表达水平.结果 (1)新生大鼠HIBD后48h结扎侧大脑半球脑水肿明显.(2) HIBD6 h出现典型的凋亡细胞峰,细胞凋亡率为(1.40±0.12)％.HIBD 48 h凋亡峰更为明显,细胞凋亡率达到( 15.86±0.98)％.缺氧缺血后与假手术组相比,差异有统计学意义(P＜0.01).(3)假手术组大鼠RhoGDI2和Bcl-2 mRNA表达水平较高(4.12±0.74、2.55±0.65),在HIBD 6 h后二者表达开始下降(3.19±0.77、1.96±0.36),48 h降低更加明显(1.04±0.18、1.06±0.17),与假手术组比较,HIBD各时间点RhoGDI2和Bcl-2 mRNA的表达均明显降低,差异有统计学意义(P＜0.01).(4)缺氧缺m后各时间点RhoGDI2 mRNA的表达和Bcl-2 mRNA的表达呈正相关(r=0.831,P＜0.05).结论 脑缺氧缺血后,随着凋亡的出现,RhoGDI2和Bcl-2 mRNA表达水平降低,提示Rh0GDI2表达失衡可能通过Bcl-2参与新生大鼠HIBD中凋亡的发生.

Changes of neuronic apoptosis, Rho GDP dissociation inhibitor 2 and Bd-2 in brain tissue of neonatal rats with hypoxic-ischemic brain damage

Objective To investigate the effect of Rho GDP dissociation inhibitor 2 (RhoGDI2) and Bcl-2 in pathogenesis of hypoxic-ischemic brain damage (HIBD).Methods Neonatal 7-day-old Sprague Dawley rats were randomly divided into sham-operation control group,HIBD 6 h group and HIBD 48 h group (n =10 per group).The apoptosis rate of brain cell was measured by flow cytometer and the expression of RhoGDI2 mRNA and Bcl-2 mRNA were detected by Real-time RT-PCR.Results ( 1 ) The ligated cerebral hemisphere of neonatal rats showed obvious edema at 48 h after hypoxia-ischemia.( 2 ) Apoptotic cell appeared at 6 h in HIBD group,the apoptosis rate was ( 1.40 ± 0.12 ) ％.The apoptosis rate obviously increased to (15.86 ±0.98)％ at 48 h after HIBD,which showed a significant increase compared to sham-operation control group ( P ＜ 0.01 ).( 3 ) The expressions of both RhoGDI2 mRNA and Bcl-2 mRNA were 4.12 ±0.74 and 2.55 ± 0.65 respectively in sham-operation control group.In HIBD group,the expressions of both RhoGDI2 mRNA and Bcl-2 mRNA began to decrease at 6 h after HIBD ( 3.19 ± 0.77,1.96 ± 0.36) and decreased furthermore at 48 h after HIBD ( 1.04 ±0.18,1.06 ±0.17 ).The differences of expression levels among three groups were statistically significant (P ＜0.01 ).(4) The expression of RhoGDI2 mRNA positively correlated with the expression of Bcl-2 mRNA ( r =0.831,P ＜ 0.05 ).Conclusion With the emerging of apoptosis after HIBD,the expressions of both RhoGDI2 mRNA and Bcl-2 mRNA are decreased.The imbalance of expression of RhoGDI2 is involved in pathogenesis of HIBD by regulating Bcl-2 expression.