Thrombopoietin Promotes Muscle Repair And Regeneration After An Acute Injury

Skeletal muscle injury is a common condition in the body,and recovery from minor injuries is possible through natural healing.However,the self-healing abilities of muscles are limited during severe injuries and can lead to irreversible scarring and even loss of skeletal muscle function;this condition may result in deficiency in normal body function and imbalance inf homeostasis.Muscle fiber regeneration is necessary to repair skeletal muscle damage.Promoting the formation and growth of regenerated muscle fibers is the best way to help skeletal muscle injury recovery.In this study,C57BL/6J mice were used to construct a model of gastrocnemius muscle injury.The mice were treated with 10 U of thrombopoietin(TPO)daily for several days for surface observation,histological analysis and gene regulation studies.The results are as follows:(1)HE staining,Western blot and q RT-PCR were used to analyze the natural repair of gastrocnemius muscle injury in mice,including the relative expression levels of Myo D,Myo G,Myostatin and TPO.The results showed that the self-repair could be completed within 9 days after the injury of gastrocnemius muscle in mice under the action of the related muscle growth regulator,and the protein expression of TPO was significantly increased in the short term(3 days)after the injury.(2)By determining the degree of muscle tissue repair,the optimal dose of TPO was selected,and the results showed that 10 U TPO had the best therapeutic effect.Evans blue staining,immunofluorescence in frozen sections,Western blot and q RT-PCR were used to study the repair effect of TPO intramusculus injection on mice.The results of Evans blue staining and immunofluorescence showed that TPO had a protective effect on the muscle fibers of the injured gastrocnemius muscle and could promote the repair of gastrocnemius muscle injury.Western blot and qrt-pcr analysis showed that TPO treatment could promote the expression of positive regulator of muscle growth(Myo D,Myo G,e My HC,Desmin and α-Actinin)and inhibit the expression of negative regulator of muscle growth(Myostatin).(3)The effects of TPO on fiber and fat content in injured skeletal muscle tissues were analyzed by Masson staining,oil red O staining,Western blot and q RT-PCR.And the results showed that TPO enhanced the production of fiber and fat in the injured gastrocnemius stroma,especially after 3 days of continuous administration.With the completion of repair,the production of fiber and fat in the stroma gradually decreased.(4)Western blot and q RT-PCR were used to analyze the possible ways of the function of promoting muscle of TPO.The results showed that TPO can promote the activation of muscle satellite cells,the proliferation of fiber/fat progenitor cells(FAPs),the phosphorylation of AKT,the increase of macrophages and the formation of new blood vessels.The results of this study indicate that TPO can promote the activation of satellite cells,the proliferation of FAPs and the phosphorylation of AKT,accelerate the inflammatory response and angiogenesis of injured skeletal muscles,and positively induce the recovery of injured muscles from multiple angles,which has a certain positive effect on the repair of acute gastrocnemius muscle injury in mice.This strategy can be used as adjuvant therapy in the clinical treatment of skeletal muscle trauma.