Inhibitory effect of (+)-catechin on oxidative stress-induced apoptosis in fibroblasts. After incubation with serum-free medium for 24 h, fibroblasts were treated for 30 min with 10 μM (+)-catechin and then subjected to oxidative stress induction with 0.1 mM hydrogen peroxide (H2O2). After 24 h, apoptosis was evaluated by TUNEL staining. (a) Microscopic findings of TUNEL staining for detection of apoptotic cells. (b) For evaluation of apoptosis, 100 cells were randomly selected and the percentage of TUNEL-positive cells was measured. Data are expressed as the mean ± SEM. **P < 0.01.