Figure 4.

Forced premature expression of the antiinflammatory cytokine IL-10 impairs normal muscle repair. (A) Recombinant IL-10 or IGF-1 (used as a control) was injected twice during the early stages of regeneration after CTX injury (Inj.). 7-d injured gastrocnemius muscles obtained from vehicle-treated mice or mice treated with IL-10 at 7 d postinjury (P.I.) were stained with an anti-eMHC antibody, and the mean area of regenerating myofibers was calculated. Bar, 50 µm. (B) WT satellite cells were cultured in GM for 24 h with 10 ng/ml IL-10, 30 ng/ml TNF, or a combination of both. (left) Cells were incubated for 1 h with BrdU, and positive cells were quantified. (right) Satellite cells were cultured in DM for 48 h with the same treatment, and Myogenin and MCK expression was analyzed. (C) Single myofibers, with their associated satellite cells, isolated from mouse muscles were cultured ex vivo in GM as in B for 72 h. Satellite cells were stained for Myogenin (Mgn; green) and TO-PRO-3 (red), and the number of positive cells in each fiber was counted. Bar, 100 µm. NT, nontreated cells. Means ± SEM of at least three experiments. **, P < 0.01.