Study On The Changes Of Zinc Transporter ZIPs Expression After Exercise-Induced Muscle Injury

Objective Zinc is one of the most abundant elements in the body,it is always been seen as a regulatory substances which involved in inflammation and muscle regeneration processes in the study of skeletal muscle injury and recovery.Recent years people found most function of zinc is depended on the regulate of zinc transporter.In this study,skeletal muscle injury was induced by downhill running model.Then investigated the variance of zinc content in serum and muscle,the changes of zinc transporters(ZIP7,ZIP8,ZIP14)expression and distribution during the muscle injury and recovery processes,and correlation analysis of various damage repair indexes and zinc transporter.It provides experimental evidence to explore the role of zinc transporters(ZIP7,ZIP8,ZIP14)in the repair of skeletal muscle injury.Methods Male SD rats(n=72,8-week-old)were divided into control group and exercise group,the exercise group then sub-divided into 0h group,6h group,12 h group,1d group,2d group,3d group,1w group,2w group(n=8)by avoirdupois.Exercise groups rats had to do downhill running of 90 minutes,which the speed was16metre/minutes,grade was-16°.Samples were collected at 0h,6h,12 h,1d,2d,3d,1w and 2w after the exercise,blood was collected from the inferior vena cava for ICP-MS,and gastrocnemius muscle was collected for ICP-MS,immunofluorescence and RT-PCR.The pictures were taken and analyzed by using Olympus DP80,microscopelaser scanning confocal microscopy lSM 700 and Image-Pro Plus 6.0software.The data was analyzed by using SPSS22.0 statistical software.Results(1)The results of serum and muscle zinc content showed that the serum zinc content decreased significantly in the first day group(P<0.05,compared with group C),and did not return to normal level in the second week;the muscle zinc content decreased significantly in the third day group(P < 0.05,compared with group 0h)(2)The results of immunofluorescence technology showed:(1)Compared with the control group,in the 0h,6h,12 h,1d group IgG was present in the muscle cells and the average fluorescence intensity was also significantly increased(P<0.05),while the distribution and content of IgG in the subsequent time group were gradually decreased.(2)The average fluorescence intensity of ZIP7,ZIP8 and ZIP14 increased significantly compared with the control group(P<0.05).The distribution of ZIP7 showed no significant change,and all of them were scattered in the distribution muscle cells.In the control group,ZIP8 was distributed on the cell membrane and showed a point-likedistribution.After the downhill running,ZIP8 was still distributed on the cell membrane,but the distribution was mostly continuous and linear.In the control group,ZIP14 was dispersed in the cell membrane and cytoplasm,and the distribution of ZIP14 in the cytoplasm changed dynamically after downhill running.ZIP14 was mainly distributed in the cytoplasm at 0h and on the cell membrane at 12 h.(3)RT-PCR results showed that the mRNA expression of ZIP7,ZIP8 and ZIP14 in the muscle increased significantly compared with the control group(P<0.05).(4)Data analysis showed that the expressions of ZIP7,ZIP8 and ZIP14 were correlated with the expressions of PIK3cg(r=-0.44,P=0.03),ERK2(r=0.52,P=0.01),Myogenin and Akt1(r=0.44,P=0.03).Conclusion(1)Running downhill caused injury to the gastrocnemius muscle of rats,and the expression of zinc transporters ZIP7,ZIP8 and ZIP14 in the muscle all increased to different degrees.The expression of ZIP8 mRNA increased in the early stage of muscle injury.The expressions of ZIP7 and ZIP14 mRNA were mainly increased in the muscle regeneration stage.The protein content of ZIP14 in muscle mainly increased in the early stage of muscle injury.The protein content of ZIP7 and ZIP8 increased mainly in the stage of muscle regeneration and repair.(2)The zinc transporter ZIP7 ZIP8,ZIP14 respectively with PIK3 cg,ERK2,Myogenin factors correlated with expression,combined with literature analysis ZIP7,ZIP8,ZIP14 expression changes may be related to cell proliferation after exercise-induced muscle damage.Increased expression of ZIP7,ZIP8,ZIP14 may have positive effects on muscle fibers regeneration after exercise-induced muscle damage.