Effect Of P38/NFκB/Il-6 On Exercise-Induced Myogenesis In Rat Skeletal Muscle

Myogenesis is the basis of muscle plasticity and muscle development.Narrow definition of myogenesis refers to the somites change into muscle tissue by proliferation,migration,differatiaion in embryo development and broad definition refers to the process of adult stem cell differentiation or fiber nucleus transcription ability's increase to increase the muscle fiber specific protein.Medical science and agronomy research.involes myogenesis in many ways for example the therapy of muscle trauma,sarcopenia and duchenne muscular dystrophy,the cultivation of livestock and poultry,exercise-induced muscle adaption and etc.Myogenesis involes a series of sophisticated molecule events of which We have deep understanding in extracellular but not little in intracellular signal pathway such as GH/IGF-1. p38/NF-KB/IL-6 which has attracted wide attention is founded in recent years.The pathway under exericse-induced environment is with no reports and myogenesis is very important in Sports Medicine so we decide to research on it.The purpose of this study:1,Following acute high or medium intensity exercise,detect the content of p38,p-p38,p65,p-p65,IL-6 mRNA,MRFs mRNA,MEF2c mRNA,the quantity and morphological changes of satellite cells,morphological changes of the myofiber and Z line.The purpose is found the function of p38,NFκB,IL-6 in myogenesis and the exercise's effection of myogenesis under different intensity exercise folling acute activity.2,Following acute high intensity exercise,with or without inhibiting p38/NFκB/IL-6 step by step detect the content of p65,p-p65,IL-6 mRNA,MRFs mRNA,MEF2c mRNA,the quantity and morphological changes of satellite cells, morphological changes of the myofiber and Z line.The purpose is vetificate sigal relaion among p38,NFκB and IL-6 folling acute activity furthermore.3,Following two weeks' high intesity exercise,detect the content of p38,p-p38,p65,p-p65,IL-6 mRNA,MRFs mRNA,MEF2c mRNA,the quantity and morphological changes of satellite cells,morphological changes of the myofiber and Z line.The purpose is found the function of p38,NFκB,IL-6 in myogenesis and the exercise's effection of myogenesis folling long-term training.The research is divided in three parts.The means and conclusions are listed below.1,The effect of acute high intensity exercise on myogenesis in rat skeletal muscle.Means:66 male SD rats was divided into 11 grounps(C1,H-0h,H-1h,H-6h,H-16h,H-24,M-0h,M-1h,M-6h,M-16h,M-24)averagely(keep range of the weight of each grounp same as far as possible).we detected p38,p-p38(WB), p65,-p-p65(ELISA),IL-6,MRFs and MEF2c mRNA(RT-PCR),microstructure of myofibers and satellites(TEM)in rat gastrocnemius after acute high,medium intensity exercise.Result and conclusion:After acute high intensity exercise,the activity of p38,p65 and IL-6 mRNA changed differently but in the span of 0-6h they all increased after acute high intensity exercise.MRFs,MEF2c mRNA increased respectively in 1-16h,1-6h.After acute medium intensity exercise,the activity of p38,p65 and IL-6 mRNA increase in post exercise 0-1h.MRFs increased at post exercise 6h and MyoD increased only at that time.MEF2c inreased in the 0-1h.Whether after acute high intensity or medium intensity,Myf-5 didn't change,so do morphological changes of satellites.The factors changed more dramasticly at same time after high intensity exercise.According to the changes,We conclude that p38/NFKB/IL-6/MyoD,MyoG,MRF4,MEF2c is a important signal pathway under the stimulation of acute high intensity but not medium exercise.That satellite unchaged in morphology suggests under the stimulation of undamaged exercise,satellite chaged slowly.Damage in myofiber wsa not necessary premise for satellite activity.It also suggests that it's myofiber but not satellite is the location of p38/NF-K B/IL-6/MyoD,MyoG,MRF4,MEF2c pathway's activity.2,The effect of acute high intensity exercise on myogenesis with p38/NF-KB/IL-6 inhibitorMeans:66 male SD rats was divided into 11 grounps(0h,0h/NF-κB,1h, 1h/NF-κB,6h,6h/NF-κB,6h/p38,16h,16h/NF-κB,16/NF-κB,24h,24/NF-κB)averagely(keep range of the weight of each grounp same as far as possible).We detected p65,-p-p65(ELISA),IL-6,MRFs and MEF2c mRNA(RT-PCR), microstructure of myofibers and satellites(TEM)in rat gastrocnemius after acute high,medium intensity exercise with or without NF-κB or p38 inhibitor.Result and conclusion:With p38 inhibitor at post exercise 6h,NF-KB,IL-6,MRFs(except for Myf-5),MEF2c mRNA decreased;With NF-KB inhibitor,at post exercise 6h,IL-6,MRFs(except for Myf-5),MEF2c mRNA decreased and at MyoG mRNA decreased at post exercise 16h..The result Confirmes the p38/NF-KB/IL-6 myogenesis signal pathway.The conclusion should be deal with prudently because PDTC is also antioxidant,p38 may effect MRFs and MEF2 directly,,NF-KB /INOS/NO can accelerate degradation of MyoD mRNA.That can interfere with the outcome of the judgement.SB203580 is only the inhibitor of p38α,βbut not the p38γwhich is also high express and activated by exercise.The function of p38γis worthy of research further.Research outcome may be different between in vitro and in vivo.Drug's injection may also effect tissues outside muscle such as nervous system and we don't know how much the drug effect the muscle.That all may be the interference.3,The effect of two weeks' high intensity exercise on myogenesis in rat skeletal muscleMeans:18 male SD rats was divided into 3 grounps(C2,48h,48h/NF-κB)averagely(keep range of the weight of each grounp same as far as possible). Detect p38,p-p38(WB),p65,-p-p65(ELISA),IL-6,MRFs and MEF2c mRNA (RT-PCR),microstructure of myofibers and satellites(TEM)in rat gastrocnemius after two weeks' high intensity exercise.Result and conclusion::After two weeks' high intensity exercise,the weight ratio of gastrocnemius/body increase,the satellite changed in morphology,the activity of p38,NF-KB,the mRNA of MyoD,Myf-5,MyoG,MEF2c increase,the IL-6 mRNA unchanged.With NF-KB inhibitor,the weight of gastrocnemius' increase decresed with the same exercise induction.That suggests that long-term high intensity train can improve myogenesis by the singal pathway—p38/NF-KB/?/MyoD,Myf-5,MyoG,MEF2c mRNA.The study don't support that IL-6 is involved in the long-term train inducing myogenesis.Full text summary.1,Acute high or medium intensity exercise in treadmill can induce the increase of activity of p38,NF-KB,the mRNA of IL-6,MRFs,MEF2c,but no change myofiber and satellite in morphology.Contrasted with acute medium intensity exercise,under high intensity exercise' stimulation,the acitivity of p38,NF-KB and IL-6 mRNA changed in concordance showing signal pathway characters more obviously2,With p38 or NF-KB inhibitor,under acute high intensity exercise's stimulation, some indexes changed less dramasticly.It confirms p38/NF-KB/IL-6/MEF2 cand MRFs is the myogenesis pathway under high intensity exercise.3,After two weeks' high intensity exercise,the basic value of MRFs,MEF2c mRNA increased,the satellite show activated in morphology and the changes decreased with NF-KB inhibitor.These result above suggests that long-term exercise induce myogesis by p38/NF-KB but not IL-6 probably.change rhythem of mRNA and protein are different so the conclusion should be treat prudently.