IGF-1对缺氧缺血性脑损伤新生小鼠脑细胞线粒体Cyt-C、caspase-3表达的影响

摘要

目的探讨胰岛素样生长因子-1( IGF-1)对缺氧缺血性脑损伤( HIBD)新生小鼠脑细胞线粒体细胞色素C( Cyt-C)、caspase-3表达的影响。方法108只新生C57/BL小鼠随机分为正常对照组、缺氧缺血( HI)组和HI+IGF-1组,改良Rice法制作新生小鼠右脑 HIBD模型。 HI+IGF-1组于HI后即刻予腹腔注射IGF-1(50μg/kg),HI组及正常对照组注射等量的生理盐水。应用Western blot和RT-PCR法检测各组皮质、海马、丘脑0、3、6、12、24和48 h Cyt-C、caspase-3蛋白和mRNA表达。结果① HI组Cyt-C、caspase-3 mR-NA及蛋白表达明显增加出现在皮质术后3 h,海马术后6 h,丘脑出现在术后12 h,明显迟于皮质及海马；② HI+IGF-1组Cyt-C、caspase-3 mRNA及蛋白表达在HI组表达明显增加的相应时间点虽较正常对照组升高,但较HI组表达明显降低,3组之间比较差异有统计学意义( P<0.05)；③ HI组皮质Cyt-C、caspase-3 mRNA及蛋白表达于术后3 h表达明显增加,6 h有所下降,12~24 h达到另一高峰,峰值时间点HI+IGF-1组的表达较HI组均降低(P<0.05)。结论 IGF-1可能通过抑制Cyt-C释放,减少caspase-3表达,发挥对新生小鼠HIBD的神经保护作用,IGF-1对皮质的保护有两个时间点。%Objective To discuss the effect of IGF-1 on the expression of cytochrome C ( Cyt-C) and caspase-3 in neonatal mice with hypoxic-ischemic brain damage ( HIBD) . Methods One hundred and eight C57/BL neonatal mice were randomly divided into normal control group ( n=36 ) and HI group ( n=36 ) and HI+IGF-1 group ( n=36 ) . Mouse HIBD model was prepared according to the Rice-Vannucci method. HI+IGF-1 group was immediately injected with 50 μg/kg IGF-1 after HI;HI group and normal control group were injected with the same amount of saline solution. RT-PCR and Western blot methods were used to measure the mRNA and protein expression of Cyt-C and caspase-3 0, 3, 6, 12, 24 and 48 h after HI. Results ①In HI group, the increase of Cyt-C and caspase-3 mRNA and protein expression intensity appeared at 3 h in cerebral cortex, at 6 h in hippocampus and at 12 h in thalamus, delayed compared with cortex and hippocampus; ② HI group Cyt-C and caspase-3 mRNA and protein expression increased compared with those in the normal control groups at the same point, and those in the HI+IGF-1 group also increased compared with that in the normal control groups, but decreased compared with that in the HI group. There was statistical significance among the groups (P<0.05);③The Cyt-C and caspase-3 mRNA and protein expression of Cortex significantly increased after 3 hours, and then decreased after 6 hours, and reached another peak value in 12~24 hours. The expressions of Cyt-C and caspase-3 mRNA in HI+IGF-1 group were lower in the two peak time than HI group (P<0.05). Conclusion IGF-1 may inhibit the release of Cyt-C, and reduce the expression of caspase-3, and provide neuroprotection against HIBD in neonatal mice. IGF-1 has two time points to protect the cortex.