PINK1基因对缺氧缺血性脑损伤新生小鼠细胞凋亡及自噬的影响

Effects of PINK1 gene on cell apoptosis and cell autophagy in neonatal mice with hypoxic-ischemic brain damage

摘要:

目的 研究PINK1 基因对缺氧缺血性脑损伤新生小鼠细胞凋亡及细胞自噬的影响。方法 将野生型和PINK1 基因敲除型新生小鼠各72 只分为野生型假手术组(SWT)、野生型模型组(MWT)、基因敲除假手术组(SKO)及基因敲除模型组(MKO)。模型组小鼠行右侧颈总动脉结扎后置于低氧舱中(含8%氧气和92% 氮气)2.5 h,假手术组不予结扎和低氧处理。缺氧缺血处理后24 h,采用TTC 染色法检测各组新生小鼠脑梗死程度;采用免疫组化法检测各组脑组织中活化型半胱天冬酶-3(CC3)的表达;采用TUNEL 法检测细胞凋亡;采用免疫荧光法及Western blot 法检测细胞自噬相关蛋白LC3 的表达。结果 MKO 组小鼠脑组织梗死程度较MWT 组小鼠明显减轻(P<0.05);脑组织凋亡阳性细胞数明显减少,凋亡指数降低(P<0.05);凋亡蛋白CC3 表达显著减少(P<0.05)。MKO 组小鼠自噬相关蛋白LC3 表达较MWT 组减少,进一步检测证实自噬指标LC3 Ⅱ/LC3 Ⅰ比值较MWT 组降低(P<0.05)。结论 敲除PINK1 基因对新生鼠缺血缺氧脑损伤具有神经保护作用。

Abstract:

Objective To study the effect of PINK1 (phosphatase and tensin homolog deleted on chromosome ten induced putative kinase 1) gene on cell apoptosis and cell autophagy in neonatal mice with hypoxic-ischemic brain damage (HIBD). Methods Seventy-two wild-type C57BL/6 mice and 72 PINK1 gene knockout neonatal C57BL/6 mice were randomly divided into four groups: sham-operated wild-type (SWT), HIBD model wild-type (MWT), shamoperated knockout (SKO) and HIBD model knockout (MKO). HIBD model was prepared by low oxygen exposure for 2.5 hours after right carotid artery ligation. After 24 hours of hypoxia-ischemia treatment, TTC (2,3,5-triphenyl four azole nitrogen chloride) staining was used to measure brain infarct volume. The immunohistochemical staining was used to measure the expression of cell apoptosis protein cleaved-caspase-3 (CC3) in brain tissues. The TUNEL method was used to measure cell apoptosis. The immunofluorescence staining and Western blot were used to measure the expression of cell autophagy protein LC3. Results Compared with the MWT group, the infarct volume of brain tissues was markedly reduced in the MKO group (P<0.05), the number of apoptotic cells and the cell apoptosis index were markedly decreased in the MKO group (P<0.05), the expression of apoptosis protein CC3 was significantly reduced in the MKO group (P<0.05), the expression of cell autophagy protein LC3 was significantly decreased in the MKO group, and the autophagy indicator LC3II/LC3I was also markedly reduced in the MKO group (P<0.05). Conclusions PINK1 gene knockout can protect neonatal mice from HIBD.