Study On The Proliferation Of β-hydroxy-β-methylbutyric Acid On The Injuried Myoblast In Tan Sheep

Delayed muscle development and impaired tissue repair are common occurrences in Tan sheep reared for mutton.Therefore,understanding the regulatory mechanisms involved in muscle growth and development is critical for animal production.Muscle cell proliferation and differentiation can be mimicked by skeletal muscle satellite cells(SMSCs),which can also be stimulated to differentiate into myoblasts.SMSCs can promote muscle tissue development.β-hydroxy-β-methylbutyric acid(HMB)is an additive commonly used in animal production.As an additive,HMB can promote the muscle growth and development of livestock.Although it has been applied in production practice,the specific molecular mechanism of muscle action has not been systematically explored by HMB.This study examined the effect of HMB on myoblast injury repair using flow cytometry,Ed U assay,RNA sequencing,Western blot,and ELISA.The main results are as follows:(1)Satellite cells of the skeletal muscle were extracted,grown,and identified.The results showed that SMSCs were flat cells with protrusions.When SMSCs were induced into myoblasts,the cells grew in spindle-shaped shape.SMSCs immunofluorescence results showed that Pax7,Myo D1 and Desmin were positively expressed,among which Pax7 and Myo D1 were expressed in the nucleus,and Desmin was expressed in the cytoplasm.(2)Dexamethasone(DEX)built into a muscle cell damage model.The results showed that DEX promotes the apoptosis of myoblasts and can be used to construct the injury model of myoblasts.HMB treatment significantly improved the proliferation of myoblasts.These results indicate that dexamethasone can successfully construct the injury model,and HMB can promote the proliferation of myoblasts and repair cell damage.(3)The transcriptome sequencing HMB proliferation mechanism is determined.The results showed that HMB inhibited the expression of IL-17 gene.HMB inhibited the IL-17 and NF-κB signaling pathways and acted on the three downstream target genes of the NF-κB pathway,IL-6,TNF-α and IL-1β.Finally,HMB could repair the damaged myoblasts.In summary,this study successfully extracted the satellite cells of Tan Yang muscle and constructed the myoblast injury model.After the injury treatment,apoptosis and proliferation were detected.In terms of the phenotype of apoptosis and proliferation cells,the molecular level was explored,and it was found that HMB not only inhibited myoblast apoptosis,but also promoted cell proliferation.HMB can reduce the expression of IL-17 gene and can be used in the IL-17 and NF-κB signaling pathways to inhibit the expression of NF-κB p65,IKB-α and Ikk-α proteins.At the same time,the protein expression of three downstream targets of NF-κB pathway(IL-6,TNF-αand IL-1β)is decreased.Thus,the effect of HMB on the damage repair of Tan sheep myoblast was realized.This study provides a new idea for the study of proliferation of Tan sheep myoblasts after injury.