Regulatory mechanism of Lijin manipulation on inflammation and apoptosis in rabbits undergoing skeletal muscle injury repair
BACKGROUND:Excessive apoptosis in skeletal muscle cells will destroy the dynamic balance of the number of myocytes,leading to pathological injury of skeletal muscle.Lijin manipulation is effective in treating skeletal muscle injury,but whether it can inhibit apoptosis and promote the repair of skeletal muscle injury is unknown.OBJECTIVE:To explore the mechanism by which Lijin manipulation reduces inflammation and apoptosis during the repair of skeletal muscle injury in rabbits.METHODS:Forty-five healthy adult Japanese white rabbits were randomly divided into blank group,model group and Lijin group(n=15 per group).No intervention was performed in the blank group.Gastrocnemius muscle percussion molding was performed in both the model group and Lijin group.After modeling,the model group was not treated,while the Lijin manipulation(Stroking,kneading,and rubbing)was performed in the Lijin group on the 3rd day,once a day,15 min/time.Sampling in each group was performed on the 7th,14th and 21st days after modeling.The general morphological structure of gastrocnemius was observed by hematoxylin-eosin staining.The ultrastructure of gastrocnemius muscle was observed by transmission electron microscopy.Apoptosis of gastrocnemius cells was observed by TUNEL staining.The expressions of interleukin-1β,interleukin-6 and interleukin-10 in gastrocnemius muscle were detected by ELISA.The protein expressions of BAX,BCL-2 and Caspase3 in gastrocnemius muscle were detected by western blot.The mRNA expression of BAX and BCL-2 was detected by RT-PCR.RESULTS AND CONCLUSION:(1)Hematoxylin-eosin staining results showed that compared with the model group,inflammatory cells decreased in number,myocyte amount increased,and muscle tissue gradually healed in the Lijin group at each observation point.(2)The results of transmission electron microscopy showed that compared with the model group,the arrangement of muscle fibers at each observation point in the Lijin group was gradually orderly,mitochondria were gradually complete,Z-line arrangement was gradually regular,and free ribosomes were gathered.(3)TUNEL staining results showed that compared with the model group,apoptosis rate in the Lijin group was gradually decreased at all observation points(P<0.05).(4)ELISA results showed that compared with the model group,the expression of interleukin-1β and interleukin-6 in the Lijin group continued to decrease(P<0.05),while the expression of interleukin-10 increased on the 7th day after modeling,and then showed a downward trend(P<0.05).(5)Western blot results showed that compared with the model group,the expression of BCL-2 protein/BAX protein in the Lijin group was significantly increased at each observational point(P<0.05).The protein expression of Caspase3 decreased significantly(P<0.001),and was gradually similar to that of the blank group.(6)RT-PCR results showed that compared with the model group,the mRNA expression level of BCL-2/BAX in the Lijin group was significantly higher at each observational point(P<0.05).To conclude,Lijin manipulation can inhibit inflammation,reduce apoptosis,and promote the repair of injured skeletal muscle.