Figure 2

Bax-null myogenic cells were more resistant than wild-type myogenic cells to cell death induced by adriamycin, staurosporine, or serum-free medium. A. Myogenic cells from Bax-null (KO, filled bars) and wild-type (WT, open bars) were grown in culture until near confluence and then exposed to either 1.7 μM adriamycin, 50 nM staurosporine, or left untreated as a control. After 24 h of treatment, the number of viable cells in each culture was determined and expressed as a percentage of the number of viable cells in the untreated cultures. After either adriamycin or staurosporine treatment, signficantly more viable cells remained in the Bax-null than in the wild-type cultures. Error bars equal SE with n = 4. P values of significance from unpaired, two-tailed, t-test. This experiment was repeated an additional two times with similar results. B. Myogenic cells from two independent, immortalized Bax-null lines (Bax KO, filled circles) and one immortalized wild-type line (WT, open circles) were grown in culture until near confluence and then switched to serum-free medium. After 1 day and 2 days of treatment, the number of viable cells in each culture was determined and expressed as a percentage of the number of viable cells on day 0 when the medium switch was made. After both one and two days in serum-free medium, significantly more viable cells remained in the each of the Bax-null cultures than in the wild-type culture (P < 0.001 by Welch alternate T-test as indicated by ***). In constrast, the two Bax KO experiments did not differ significantly from each other. Error bars equal SE with n = 12 to 24.