Fig. 1. Inhibition of both spontaneous and induced mpc apoptosis by MPs. (A,B) untreated (A) and STS-treated (B) mpcs were co-cultured with MPs at various ratios and mpc apoptosis was evaluated by annexin V labelling (white bars) and DIOC-6 staining (black bars) after exclusion of CD14⁺ cells. In A, all mpc:MP ratios used were statistically different from mpcs (1:0 ratio) (P0.04); in B, all mpc:MP ratios used, except the 1:0.5 ratio, were statistically different from mpcs (1:0 ratio) (P0.07). (C,D) STS-treated myoblasts (C, Mb) and myotubes (D, MT) were co-cultured with or without MP (1:2 mpc:MP ratio). Apoptosis was evaluated by caspase-3 activity measurement. Results are means ± s.e.m. of at least three experiments.