Fig. 1. Biochemical (A) and morphological (B) evidence for H₂O₂-induced loss of human skin fibroblasts. Cell viability was determined by measuring LDH activity in conditioned media (A); cells in apoptosis were determined morphologically by Hoechst 33258 staining (B). Cells were exposed to 1 mM H₂O₂ for 15 minutes, washed and analysed at different times after the lesion, as indicated at the bottom of A and in inserts in B. Bars represent mean±s.e.m. of at least three different experiments and are from three separate cell preparations. Arrows in B indicate cells in apoptosis. ^*P<0.01 versus 0 time.