Effects Of Acute Downhill Running On EIF2? And Related Proteins In Skeletal Muscle Of Mice

Objective:Acute downhill running can cause delayed muscle soreness.Delayed muscle soreness causes a decrease in muscle contraction and affects the daily physical activity and the athlete's training.At present,the mechanism of the delayed onset muscle soreness is still inconclusive,and inflammation is one of the current research hotspots.Related studies have shown that phosphorylated eIF2? can regulate immune responses.Therefore,this study investigated the effects of an acute downhill running exercise on eIF2? and its related proteins in mouse skeletal muscles and investigated whether eIF2? changes after acute downhill running.The mechanism of regulating delayed-onset muscle soreness relieves the symptoms of delayed onset muscle soreness,seeks effective treatment methods,and provides theoretical basis for improving the effect of sports training.Methods:We use C57BL/6 mice as the subjects,sixteen 8-week-old male C57BL/6 mice were randomly divided into control group(WC group)and exercise group(WE group),8 mice in each group.The mice in the exercise group performed an acute downhill run with a slope of-16°,a speed of 16 m/min,and sustained exercise for 90 min.The mice in the control group did not exercise.In the exercise group 24 hours after the end of exercise,the two groups of mice were hydrated with chloral aldehyde after abdominal anaesthesia.The blood samples were taken from the abdominal aorta and EDTA was anticoagulated.After 30 minutes of standing,routine blood tests were performed to observe changes in blood-related immune parameters.Bilateral quadriceps femoris muscles were harvested from mice.HE staining was used to observe the changes of cell morphology in quadriceps femoris;immunohistochemical staining of neutrophils was performed to calculate the expression area of neutrophils;quadrafacial neutrophils were expressed.The relative molecular expressions of p-eIF2?,eIF2?,IL-6,IL-12,PKR and TGF-P protein in skeletal muscle were detected by western blot.Data were analyzed using the SPSS 21.0 independent sample t-test..Results:1)The percentage of blood neutrophils in the exercise group was significantly lower than that in the control group;2)HE staining showed muscle cell swelling and nuclei increase in the exercise group;3)Immunohistochemistry results showed that the expression of neutrophils in the exercise group was significantly higher In the control group(p<0.05);4)The relative expression of IL-6 and TGF-? protein in the skeletal muscle of the exercise group was significantly higher than that in the control group(p<0.05),while the relative expression of IL-12 protein in the skeletal muscle of the exercise group The amount of PKR protein was significantly decreased compared with the control group;5)Compared with the control group,the relative molecular expression of PKR protein in the exercise group was significantly decreased(p<0.05),and the relative molecular expression of the eIF2? protein was not significantly changed(p>0.05).The p-eIF2? protein was relatively The molecular expression was significantly increased(p<0.05).1)Conclusion:1)Acute downhill running increases the phosphorylation of eIF2?,and phosphorylation of eIF2? may regulate the inflammatory response after acute downhill running;2)After downhill running,the increase in phosphorylation of eIF2?was not caused by PKR kinase.