| Objective:By detecting the changes of Apelin,UCP3,Mfn2 and Nrf2 expression in skeletal muscle of SD rats immediately,24h and 48h after exhaustive centrifugal exercise or blunt contusion,to explore the temporal expression and change mechanism of energy metabolism related factors in skeletal muscle after different injuries,so as to provide some useful information for the recovery of skeletal muscle injury.Methods:42 SD rats were selected as the research object,and one control group and six experimental groups were set up:quiet control group（C）,immediately after exhaustive centrifugal exercise（E0）,24h after exhaustive centrifugal exercise（E24）,48h after exhaustive centrifugal exercise（E48）,immediately after blunt injury（D0）,24h after blunt injury（D24）and 48h after blunt injury（D48）,with 6 rats in each group.The control group was anesthetized by intraperitoneal injection.The gastrocnemius muscle of the rat hind leg was taken and divided into two parts.One was used as the experimental sample of real-time PCR and the other was used as the sample of Western blot.The materials of the experimental group:the materials of the exhaustive exercise group and the contusion group were taken immediately,24h and 48h after exhaustion and contusion,respectively.The method of taking materials was similar to that of the control group.Results:（1）The results of Apelin PCR:compared with group C,the expression of Apelin mRNA in skeletal muscle of rats in EO group was significantly higher（P<0.05）,and there was no significant difference between E24 and E48 groups;Compared with EO group,there was no significant difference between E24 group and E48 group.Compared with group C,Apelin mRNA expression in skeletal muscle of rats in D0 and D48 groups increased significantly（P<0.05,P<0.01）,but there was no significant difference in D24 group;Compared with DO group,the expression of D24 group and D48 group decreased significantly and increased significantly respectively（P<0.05,P<0.01）.（2）PCR results of UCP3:compared with group C,the expression of UCP3 mRNA in skeletal muscle of E0 group was significantly up-regulated（P<0.05）,and there was no significant difference between E24 group and E48 group;Compared with E0 group,there was no significant difference in the expression of E24 group,and the expression of E48 group was significantly down-regulated（P<0.05）.Compared with group C,there was no significant difference in the expression of UCP3 mRNA in skeletal muscle of D0 group,but the expression of UCP3 mRNA in D24 group and D48 group increased significantly（P<0.05,P<0.01）;Compared with D0 group,the expression of D24 group and D48 group was significantly up-regulated（P<0.05,P<0.01）.（3）PCR results of Mfn2:compared with group C,there was no significant difference in the expression of Mfn2 mRNA in skeletal muscle between E0 group and E48 group,and the expression of Mfn2 mRNA in E24 group was significantly up-regulated（P<0.05）;Compared with E0 group,there was no significant difference between E24 group and E48 group.Compared with group C,the expression of Mfn2 mRNA in skeletal muscle of rats in D0 group and D48 group was significantly up-regulated（P<0.05,P<0.01）,but there was no significant difference in D24 group;Compared with D0 group,the expression of D24 group decreased significantly（P<0.05）,while the expression of D48 group increased significantly（P<0.01）.（4）PCR results of Nrf2:compared with group C,the expression of Nrf2 mRNA in skeletal muscle of rats in E0 group and E24 group increased significantly（P<0.05,P<0.01）,and there was no significant difference in the expression of E48 group;Compared with E0 group,there was no significant difference between E24 group and E48 group.Compared with group C.the expression of Nrf2 mRNA in skeletal muscle of rats in D0 group and D48 group increased significantly（P<0.01）,and the expression of Nrf2 mRNA in D24 group increased significantly（P<0.05）;Compared with D0 group,there was no significant difference in the expression of D24 group,and the expression of D48 group increased significantly（P<0.01）.（5）Western blot results of Nrf2:compared with group C,the expression of Nrf2 protein in skeletal muscle of rats in E0 and E24 groups was significantly up-regulated（P<0.05）,there was no significant difference in E48 group,and there was no significant difference in E24 and E48 groups compared with E0 group.Compared with group C,there was no significant difference in the expression of Nrf2 protein in skeletal muscle between group D0 and group D24,but the expression of Nrf2 protein in group D48 was significantly up-regulated（P<0.01）;Compared with D0 group,there was no significant difference in the expression of D24 group,and the expression of D48 group increased significantly（P<0.01）.Conclusion:（1）Immediately after exhaustive exercise,except Mfn2,the gene expression of three other metabolic related factors in skeletal muscle increased significantly,suggesting that early energy demand and skeletal muscle micro injury after exhaustive exercise can promote the significant expression of Apelin,UCP3 and Nrf2,while the expression of Mfn2 increased significantly 24 hours after exhaustive exercise,It is possible that Mfn2’s function of promoting energy supply and injury recovery through mitochondrial fusion lags behind the other three factors.At 48h after exhaustive exercise,with the decrease of energy metabolism demand in the recovery period and the recovery of skeletal muscle micro injury,the expression levels of the four factors decreased to the quiet level.（2）After skeletal muscle contusion,the gene expression levels of four energy metabolism related factors in this study increased significantly,and the expression levels increased significantly 48 hours after contusion.Therefore,the expression level of skeletal muscle energy metabolism related factors after contusion may be higher than exhaustive exercise,especially in the later stage of injury.It is speculated that the injury degree of blunt injury is more serious,and the expression levels of four factors need to be up-regulated for a long time to slow down oxidative stress injury and regulate cell apoptosis,autophagy and muscle regeneration,so as to increase the energy demand in the process of injury recovery.（3）After exhaustion exercise and blunt contusion,the expression of Nrf2 protein in skeletal muscle was consistent with the trend of mRNA expression,and it is speculated that after both injuries,the high expression of Nrf2 protein in skeletal muscle can play a role in inhibiting ROS production,regulating mitochondrial respiration and autophagy,and preventing skeletal muscle atrophy and fibrosis. |
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