Cell survival. INS-1E cells were exposed to ZnCl2(A, B) or TPEN (C, D) for 24 h in the presence of 11 mM glucose. (A, C) cell viability and DNA fragmentation. (B, D) Bax/Bcl-2 gene expression. In cells exposed to ZnCl2, gene expression was normalized for β-actin, HSP, and Cltc. In cells exposed to TPEN, gene expression was normalized for HSP, CycA, and UBC-7. Data are shown as the mean ± SEM (n = 4–6). *P < 0.05.