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

Abstract: 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.

CSTR: 32200.14.cjcb.2005.02.0021