FIG. 8.
Effects of ceramide on muscle cell viability. L6 myoblasts transiently transfected with pCMV5 lacking or containing cDNA encoding wild-type PKCζ, kd-PKCζ, or PKB T34A were incubated with either vehicle alone (dimethyl sulfoxide), C2-ceramide (Cer, 100 μM, 2 h), or C2-ceramide (100 μM, 2 h) plus Ro 31.8220 (5 μM, added 15 min prior to ceramide). Ceramide promotes detachment and death of myoblasts, and thus viable cells were those that remained adherent, displayed trypan blue exclusion, and stained positively for DAPI. (A and C) Representative images of DAPI-stained L6 cells; (B and D) quantitative analysis of viable cells from five randomly chosen visual fields. Cell loss was expressed as a percentage change in cell number relative to that from the appropriate untreated experimental cell population. Asterisks signify significant changes (P < 0.05) between the indicated bars or compared to an untreated cell population, as determined by one-way analysis of variance.