Figure 2.

Immunoblots of caspases, calpains, and their substrates in RPE cells cultured under hypoxia: (lane 1) initial, (lane 2) 1-day normal, (lane 3) 1-day hypoxia, (lane 4) 2-day normal, (lane 5) 1-day hypoxia/1-day reoxygenation, (lane 6) 2-day hypoxia, (lane 7) 3-day normal, and (lane 8) 2-day hypoxia/1-day reoxygenation. (A) caspase-3, (B) calpain 1, (C) calpain 2, (D) α-spectrin, a substrate for both capase-3 and calpain, and (E) β-actin (nonsubstrate gel-loading control). The bar graphs show the densities of bands for (F) α-spectrin fragments at 145-kDa (calpain-specific) normalized to β-actin and expressed as means ± SEM (n = 3). *P < 0.05 relative to the corresponding normal group (Dunnett's t-test).