Effect of COX-2 on apoptosis induced by UUO. A and B: cortical caspase-3 protein abundance in COX-2−/− and WT mice subjected to 3 days (A) or 7 days (B) of UUO (n = 6). C and D: cortical cleaved caspase-3 protein abundance in COX-2−/− and WT mice subjected to 3 days (C) or 7 days (D) of UUO (n = 6). E: TUNEL staining of the cortical region from COX-2−/− and WT mice subjected to 3 or 7 days of UUO. F: TUNEL staining of the medullary region from COX-2−/− and WT mice subjected to 3 or 7 days of UUO. Green, TUNEL-positive cells; blue, counterstaining with DAPI. Original magnification: ×20. G: quantification of the cortical apoptotic index (TUNEL-positive cells per field) in COX-2−/− and WT mice subjected to 3 or 7 days of UUO. H: quantification of the medullary apoptotic index (TUNEL-positive cells per field). Data are presented as means ± SE; for 3-day UUO, sham WT mice: n = 4, sham COX-2−/− mice: n = 4, 3-day UUO WT mice n = 4, and 3-day UUO COX-2−/− mice: n = 2; for 7-day UUO, sham WTmice: n = 5, sham COX-2−/− mice: n = 3, 7-day UUO WT mice: n = 4, and 7-day UUO COX-2−/− mice: n = 3. *P < 0.05; **P < 0.01; ***P < 0.001.