Fig 2: Effect of Mstn knockdown and training on relative mRNA expression of Pax7 and MyoD in gastrocnemius muscle. (A) Quantitative RT‐PCR analysis of Pax7 mRNA levels in Mstn−/− muscle. (B) Quantitative RT‐PCR analysis of MyoD mRNA levels in Mstn−/− muscle. (C) Quantitative RT‐PCR analysis of Pax7 mRNA levels following siRNA‐mediated Mstn knockdown ± exercise. (D) Quantitative RT‐PCR analysis of MyoD mRNA levels following siRNA mediated Mstn knockdown ± exercise. C = control group, T = training group, si = treatment with siRNA, siT = training + siRNA. KO = Mstn−/− mice, WT = wild‐type mice. Values are presented as means ± SD. n = 7 per group. *P < 0.05 significantly different from control group.

Fig 3: Effects of Mstn knockdown and exercise on visceral body fat content and serum levels of leptin. (A) Visceral fat mass following siRNA‐mediated Mstn knockdown. (B) Serum levels of leptin following siRNA‐mediated Mstn knockdown. (C) Serum levels of leptin in Mstn −/− mice. C = control group, T = training group, si = treatment with siRNA, siT = training + siRNA. KO = Mstn −/− mice, WT = wild‐type mice. Values are presented as means ± SD. n = 7 per group *P < 0.05 significantly different from control group.

Fig 4: Effect of Mstn knockdown and training on follistatin mRNA expression of gastrocnemius muscle and serum protein level. (A) Quantitative RT‐PCR analysis of follistatin mRNA levels in Mstn −/− muscle. n = 5 per group, *P < 0.05 significantly different from WT. (B) Quantitative RT‐PCR analysis of follistatin mRNA levels following siRNA‐mediated Mstn knockdown ± exercise. n = 7 per group, *P < 0.05 significantly different from control group. (C) Immuno‐PCR analysis to determine serum concentration of follistatin from Mstn −/− mice. n = 5 per group, *P < 0.05 significantly different from WT. (D) Immuno‐PCR analysis to determine serum concentration of follistatin following siRNA‐mediated Mstn knockdown ± exercise. n = 7 per group, *P < 0.05 significantly different from control group. C = control group, T = training group, si = treatment with siRNA, siT = training + siRNA. KO = Mstn −/− mice, WT = wild‐type mice. Values are presented as means ± SD.

Fig 5: Effect of myostatin inhibition (after myostatin knockout [Mstn -/-], AAV-mediated overexpression of myostatin propeptide [AAV Prop] and siRNA-mediated Mstn knockdown) on myostatin propeptide mRNA levels and serum protein levels. (A) Quantitative RT-PCR analysis of Mstn mRNA levels in Mstn -/- extensor digitorum longus (EDL) and soleus muscles (primers targeting exons 2/3). n = 5 per group, *P < 0.05 (B) Quantitative RT-PCR analysis of myostatin propeptide mRNA levels in Mstn -/- muscle (primers targeting exons 1/2). n = 5 per group (C) Quantitative RT-PCR analysis of Mstn mRNA levels in AAV Propeptide treated tibialis anterior (TA) muscle (primers targeting exons 2/3). n = 6 per group *P < 0.05 (D) Quantitative RT-PCR analysis of myostatin propeptide RNA levels in AAV Propeptide-treated TA muscle (primers targeting exon 1/2). n = 6 per group, *P < 0.05 (E) Immuno-PCR analysis to determine serum concentration of myostatin propeptide (MYOPRO) from Mstn -/- mice. n = 5 per group, *P < 0.05. (F) Immuno-PCR analysis to determine serum concentration of MYOPRO following siRNA-mediated Mstn knockdown ± exercise. n = 7 per group, *P < 0.05 significantly different from control group. C = control group, T = training group, si = treatment with siRNA, siT = training + siRNA. KO = Mstn -/- mice, WT = wild-type mice. Values are presented as means ± SD.