The Effect of Voluntary Running Wheel Exercise on Mitochondrial Protein Import Machinery（PIM）Components in C57BL/6 Mice Skeletal Muscle

Objective:This study was focused on the effect of voluntary running wheel exercise on mitochondrial protein import machinery(PIM)components in mice skeletal muscle.We explored the PIM in terms of sports science,so as to provide new experimental evidence for the mechanism of mitochondria in the movement promoting the health.Methods:We chose 20clean4-week-old male C57BL/6 mice,which were randomly divided into control group(N)and voluntary running wheel exercise group(E).Group E proceeded 8weeks running wheel movement.At the end of the exercise intervention,the mice were sacrificed after fasting 12 hours,removed the quadriceps quickly.We assayed the mRNA level of PIM components-mitochondrial translocase of the outer membrane(Tom20,Tom40),mitochondrial translocase of the inner membrane(Tim22),voltage dependent anion channel(VDAC3),the key molecule of mitochondrial biogenesis P53,PIM chaperone HSPA1 and endoplasmic reticulum stress molecules Bip with RT-PCR.Simultaneously,we detected the protein content of P53、Tom40、Tim22and HSPA1 with Western-blot.Results:The effect of voluntary running wheel exercise on the transcriptional level of Tom40,Tom20,VDAC3 and Bip molecules were significant(P <0.05),especially on Tom40,but there were no significant effect on the mRNA levels of P53 and TIM22(P>0.05).The voluntary running wheel movement significantly increased the protein expression of HSPA1(P <0.05),but significantly reduced the protein content of Tim22(P<0.01).However,there were no significant effect of running wheel exercise on protein expression of P53 and Tom40(P>0.05).Conclusion:The voluntary running wheel exercise can promote gene expression of classical PIM pathway components(Tom40,Tom20,VDAC3),and endoplasmic reticulum stress molecules Bip,while the movement raises the protein expression of chaperone HSPA1 of PIM.But voluntary running wheel movement down regulates the protein expression of non-classical PIM pathway components Tim22,indicating that there may be different affection of exercise on different PIM pathways.