Effects Of Adipose Mesenchymal Stem Cells Injected Intramuscularly On Myostatin Signaling Skeletal Muscle In Rats After Eccentric Exercise

Abstract

PURPOSE: To observe the effect of adipose mesenchymal stem cells (ASCs) on myostatin signal of skeletal muscle in rats at different time points after eccentric exercise, and to explore the mechanism of ASCs injection on skeletal muscle injury and repair after eccentric exercise. METHODS: Phosphate buffer saline (PBS) were injected into the gastrocnemius muscle in the left leg, and ASCs were injected into the gastrocnemius muscle of the right leg of SD rats after eccentric exercise. The rats were randomly divided into four groups: one day D1, three days D3, seven days W1 and fourteen days W2 after exercise. Skeletal muscle ultrastructure was observed by electron microscopic. The content of serum creatine kinase (CK), skeletal muscle troponin I (sTnI), myostatin (MSTN), follistatin (FST) were measured by ELISA. Real-time PCR was used to detect the expressions of MSTN, ACVR2B, FST mRNA in skeletal muscle. The expression of MSTN, ACVR2B, FST, p-Smad2/3 were detected by Western Blot. RESULTS: Compared with group PBS, adipose mesenchymal stem cell injection significantly promoted the repair of muscle fibers. Compared with group D1, the level of CK in group W2 was significantly decreased, the content of sTnI level in group D3 and group W1 were remarkably increased, the serum MSTN contents in group W1 were significantly decreased, which in group W2 was remarkably increased. Compared with group PBS, the relative expression quantities of MSTN mRNA were significantly decreased at time point D3 and which were extremely significantly down-regulated at time point W2. Compared with group PBS, the expression of MSTN protein were significantly decreased at time point D3, the expression of ACVR2B protein were remarkably increased at time point D1,D3 and W1, however, which was significantly decreased at time point W2. Compared with group PBS, the phosphorylation of Smad2/3 shown significantly decreased at the time point W2 of group ASCs. CONCLUSIONS: After eccentric exercise, allogeneic adipose mesenchymal stem cells injected intramuscularly can decreased the transcription of MSTN in skeletal muscle. Adipose mesenchymal stem cells injected intramuscularly may improve the regeneration and repair of skeletal muscle after eccentric exercise through affecting the downstream signaling pathway of MSTN.