Figure 6. The iHTM cell nuclei staining by Hoechst33258 for apoptosis detection after tBHP exposure with or without pretreatment with SB203580. iHTM cells not treated with tBHP or SB203580 were set as control (A). The nuclei of control cells were homogeneously blue after staining by Hoechst33258 (A). After exposure of tBHP for 1 h without pretreatment with SB203580, many cells were apoptotic. The nuclei of apoptotic cells were compact and condensed, which were heterogeneously stained (B). After 2 h, more cells were apoptotic (C). However, in the cells pretreated with SB203580, the percentages of apoptotic cells were less (D and E).