多聚ADP-核糖聚合酶抑制剂对高浓度锌损伤PC12细胞的保护作用

Protective Effects of Poly(ADP-bibose) Polymerase Inhibitor on Zinc-injured PC12 Cells

探讨多聚ADP-核糖聚合酶(PARP)抑制剂3-氨基苯甲酰胺(3-AB)对400μmol/L氯化锌损伤PC12细胞的保护作用及其对锌造成的细胞死亡类型的影响。应用MTT法,免疫细胞化学和Western印迹分别测定PC12细胞的存活率和PARP活性;用Hoechst33342/PI荧光双染色、膜联蛋白V结合实验及DNA断裂分析等方法检测细胞死亡类型。结果表明:在400μmol/L氯化锌的作用下,细胞存活率降至(22.7±4.6)%,PARP活性增强,坏死、凋亡和正常细胞百分比分别为(58.4±6.3)%、(18.0±5.6)%及(23.6±4.2)%;3-AB使细胞存活率提高至(76.9±4.7)%,PARP活性减弱,坏死细胞百分数降至(19.2±5.2)%,而正常和凋亡细胞百分数增加到(43.3±1.9)%和(37.5±6.5)%。实验证明,PARP参与了高浓度锌诱导的PC12细胞损伤,抑制PARP活性可提高细胞的存活率,而这种保护作用在于减少细胞的坏死而非凋亡。

This study examined the effects of the poly(ADP-ribose) polymerase (PARP) inhibitor, 3- aminobenzamide (3-AB), on PC12 cells injured by 400 μmol/L zinc chloride and on the types of zinc-induced cell death. MTT assay, immunocytochemistry and Western blot were used to assess the viability and PARP activity of PC12 cells. Hoechst 33342 / PI dual staining, Annexin V binding assay and DNA agarose gel electrophoresis were employed to investigate the types of the cell death. Our results revealed that 400 μmol/L zinc chloride promoted PARP activation and reduced the cell viability to (22.7 ± 4.6)%. (58.4 ± 6.35)% and (18.0 ± 5.6)% of PC12 cells underwent necrosis and apoptosis, respectively, and the percentage of normal cells was (23.6 ± 4.2)%. However, pre-treatment of the cells with 3-AB attenuated zinc-induced PARP activity markedly, and increased the cell viability to (76.9 ± 4.7)%. The percentages of necrotic, apoptotic or normal cells were (19.2 ± 5.2)%, (37.5 ± 6.5)% and (43.3 ± 1.9)%, respectively. The present study demonstrated that PARP participated in the zinc-induced injury of PC12 cells. Inhibition of PARP promoted the viability of zinc-injured PC12 cells significantly and this protective effect was due to a decrease in numbers of necrotic, but not apoptotic cells.