Dose-time Effect Of Lactic Acid Stimulation On IL-15 In Skeletal Muscle Of Mice

AIM: To construct a model of simulated exercise stimulated by lactic acid and evaluate the effects of different lactic acid concentration and stimulation time on muscle factor IL-15.It provides reference for modern sports training and mass fitness to choose exercise intensity and exercise time.METHODS: By injecting different concentrations of sodium lactate solution into quadriceps femoris of mice,the changes of IL-15 content and IL-15 expression in skeletal muscle of mice were detected.The experiment was divided into two parts.The first part was to detect the effect of lactic acid stimulation on IL-15 content in skeletal muscle of mice by ELISA.The second part was to detect the effect of lactic acid stimulation on IL-15 expression in skeletal muscle of mice by RT-PCR.The subjects of ELISA were 156 adult Kunming male mice weighing 18± 22 g.They were divided into 26 groups with 6 mice in each group.Lactic acid concentration included blank group,4 mmol/L group,8 mmol/L group,16 mmol/L group,32mmol/L group and 64 mmol/L group.Time includes: instant,5 minutes,15 minutes,30 minutes,1 hour.RT-PCR was used to detect 33 adult Kunming male mice,weighing 18±22 g.They were divided into 11 groups with 3 mice in each group.Lactic acid concentration included blank group,saline group,4 mmol/L group,8mmol/L group and 16 mmol/L group.The time included immediate group,5 minutes group and 15 minutes group.SPSS17.0 was used for one-way ANOVA.RESULTS:(1)The dose effect of lactic acid stimulation on IL-15 content in skeletal muscle of mice: immediate group,5 min group,15 min group,30 min group and 1 h group showed that lactic acid stimulation had a significant promoting effect on IL-15 content(P?0.05).Among them,5 min group,15 min group,30 min group and 1 h group showed significant effect(P?0.01),and lactic acid concentration of 8mmol/L and 16 mmol/L was the turning point of IL-15 content increase.(2)Time effect of lactic acid stimulation on IL-15 content in skeletal muscle of mice: 8 mmol/L group,16 mmol/L group,32 mmol/L group and 64 mmol/L group all showed significant effect on IL-15 content(P ?0.05).However,no significant change rule was found.(3)Dose effect of lactic acid stimulation on IL-15 mRNA expression inskeletal muscle of mice: immediate group,5 min group and 15 min group all showed that lactic acid stimulation promoted the expression of IL-15 mrna.Among them,immediate group and 15 min group showed significant effect(P ? 0.01).(4)Time effect of lactic acid stimulation on IL-15 gene expression in skeletal muscle of mice:The time of display in 4 mmol/L group and 16 mmol/L group had significant effect on IL-15 expression(P?0.05),but no obvious change rule was found.However,it was found that the expression of IL-15 was the best in all three groups when stimulated by lactic acid for 5 minutes.CONCLUSION:(1)Within a certain range,with the increase of exercise intensity,the health effects of exercise training on the body are more obvious.The exercise effect of moderate and high intensity exercise is the most sensitive.(2)Within an hour,the health promotion effect appeared after high school and low school exercise,but the time points were different.(3)Interleukin-15(IL-15)expression increased significantly during moderate and high intensity exercise.(4)Within 15 minutes,the expression of IL-15 mRNA increased temporarily in both high and low intensity exercise and 5 minutes.