Fig. 3
Loss of SOCS3 in mature myofibers in vivo enhances the inflammatory response after myotoxic injury. Control (SOCS3fl/fl MCK-Cre−) and SOCS3 MKO (SOCS3fl/fl MCK-Cre+) mice were either left uninjured (UN) or received a single 40 μL injection of notexin (10 μg/ml) into the right TA muscle and then killed for analysis at 1 day (D1), 2 days (D2), 3 days (D3), 5 days (D5), 7 days (D7), or 14 days (D14) post-notexin injury. a Western immunoblotting for phosphorylated and total STAT3 protein levels was performed on protein extracted from remaining OCT embedded muscles following tissue sectioning. Representative immunoblots for phosphorylated (top) and total (bottom) STAT3 protein levels are shown. Band intensity was quantified using ImageQuant software (Bio-Rad Laboratories) and the ratio of phosphorylated/total STAT3 protein levels was determined. b Representative sections immunostained with F4/80 (green) and DAPI (blue) of the TA muscle from uninjured or day 1, 2, 3, 5, 7, or 14 injured control and SOCS3 MKO mice. c Representative sections immunostained with CD68 (red) and DAPI (blue) of the TA muscle from uninjured or day 1, 2, 3, 5, 7, or 14 injured control and SOCS3 MKO mice. qRT-PCR using primers to detect IL-6 (d), IFN-γ (e), TNF-α (f), F4/80 (g), and CD68 (h) was performed on RNA extracted from snap frozen muscles following dissection. Data are expressed as mean ± SEM. Statistical analysis was performed using a two-way ANOVA with a Fisher’s LSD post hoc multiple comparisons test to determine the effects of genotype and time. n = 8 mice/time-point/genotype. **P < 0.01, ***P < 0.001, ****P < 0.0001 compared to control. Scale bar = 50 μm