Fig. 9

Upregulated IL-1β inhibits muscle differentiation in A/J myoblasts. a Quantitation of myotube fusion in WT or A/J myoblasts treated with indicated concentrations of IL-1β for 72 h. Percent myotube fusion was calculated from MyHC-positive immunostaining. b Quantitation of MyoD-positive cells are shown as percent of total nuclei in WT or A/J myoblast cultures treated with indicated concentrations of IL-1β for 72 h. c Immunofluorescence staining of myoblast cultures after treatment with an IL-1β blocking antibody (IL-1β mAb). WT and A/J cultures were plated at equal density and treated with 4 ng/ml of IL-1β mAb for 72 h. Control cultures were treated with equimolar concentrations of mouse IgG. Fixed cultures were stained with anti-MyoD (green) and anti-MyHC (red) antibodies. d Quantitation of myotube fusion in treated cultures. e Quantitation of MyoD-positive cells in treated cultures. f–h Gene expression of MyoD (f), Myf5 (g), and myogenin (h) determined by qRT-PCR in cultures treated with indicated concentrations of IL-1β mAb. n = 3. Data are shown as means ± SEM. *P < 0.05; **P < 0.01; ***P < 0.005