The Effect And Mechanism Of Aerobic Exercise Combined With Oyster Peptide On The Attenuation Of Skeletal Muscle Caused By PADAM In Rats

Objective:(1)To explore the intervention and interaction of aerobic exercise and oyster peptides on PADAM.(2)To investigate the intervention and physiological mechanism of aerobic exercise and oyster peptides on the muscle attenuation associated with PADAM formation.Method:Fifty SPF SD male rats were five-week-old and 10 rats were randomly selected as a natural control group(NC,n=10).The remaining rats were injected with cyclophosphamide(20 mg/Kg for 5 consecutive days)to construct a model for PADAM formation.Rats injected with cyclophosphamide were randomly divided into 4 groups:testosterone partial deficiency control group(PC,n-10),testosterone partial deficiency syndrome+exercise intervention group(PE,n=10),testosterone partial deficiency sign+oyster Peptide group(PO,n=10)and testosterone partial deficiency sign+exercise+oyster peptide intervention group(POE,n=10).The PC and PO groups did not exercise normally;the PE and POE groups exercised without weight-bearing swimming for 60 minutes;the oyster peptides were administered 30 minutes after the end of each training,and the supplemental dose was 1.2 g/Kg body weight.The weight is measured on time every week.After 6 weeks,the morphological structure of skeletal muscle was observed to detect the contents of TT,FT andIGF-1 in serum of skeletal muscle,TT,IGF-1,MSTN content in skeletal muscle and phosphorylation of Akt and mTOR in skeletal muscle.P70S6K mRNA expression of 4EBP-1 and eEF2 explored the intervention and mechanism of aerobic exercise combined with oyster peptide on skeletal muscle attenuation induced by PADAM formation.Results:(I)Compared with the NC group,the SI ratio of the PC group was significantly decreased(P<0.01).Two-way analysis of' variance showed that the exercise-induced skeletal muscle SI ratio was significantly increased(P<0.05),and aerobic exercise combined with oyster peptide had an interaction with SI ratio changes(P<0.05).The results of HE staining showed that the skeletal muscles of the NC group were arranged neatly,the cell boundaries were distinct,the cross section of the muscle cells was polygonal,and the nucleus was at the cell edge.The muscle bundle of the skeletal muscle of the PC group was obviously disordered,and the muscle fibers were rounded,the cross-sectional area was atrophy,and the nucleus was found.Centralization trend;compared with the PC group,the skeletal muscle fibers in the PO,PE,and POE groups were arranged neatly,the muscle fibers were rounded,and the nuclear centralization was improved.(2)Compared with the NC group,the serum levels of TT,FT andIGF-1 in the PC group were significantly decreased(P<0.01).Two-way analysis of variance showed that both aerobic exercise and oyster peptide supplementation significantly increased serum TT and FT levels(P<0.01)and IGF-1 significantly(P<0.05).Aerobic exercise combined with oyster peptide had an interaction with serum FT changes in rats(P<0.05).(3)Compared with the NC group,the levels of TT,IGF-1 and Pro in the skeletal muscle of the PC group were significantly decreased(P<0.05,P<0.01,P<0.01),and the MSTN was significantly increased(P<0.01).Two-way analysis of variance showed that aerobic exercise significantly increased the levels of TT,IGF-1 and Pro in skeletal muscle of rats(P<0.05,P<0.01,P<0.01),and MSTN was significantly reduced(P<0.01);oyster peptide supplementation significantly increased skeletal muscle TT,IGF-1 and Pro levels(P<0.05),MSTN significantly decreased(P<0.05);and aerobic exercise combined with oysters Peptides interacted with IGF-1 and MSTN levels in rat skeletal muscle(P<0.05,P<0.01).(4)Compared with the NC group,the p-Akt and p-mTOR of the PC group were significantly decreased(P<0.01,P<0.05),the expression of eEF2 was significantly decreased(P<0.05),and the 4EBP-1 was extremely significant increase(P<0.01).Two-way analysis of variance showed that aerobic exercise significantly increased p-Akt and p-mTOR in rat skeletal muscle(P<0.01,P<0.05),and P70S6K and eEF2mRNA expression increased significantly(P<0.01).4EBP-1 mRNA content decreased significantly(P<0.05);oyster peptide supplementation significantly increased p-Akt and p-mTOR in rat skeletal muscle(P<0.05),and 4EBP-1 decreased significantly(P<0.01).There was an interaction between aerobic exercise and oyster peptide supplementation on the expression of p-mTOR,4EBP-1 and eEF2 mRNA in rat skeletal muscle(P<0.05,P<0.01,P<0.05).Conclusion:(1)The PADAM rat model replicated in this study was successful,and the occurrence of PADAM caused skeletal muscle attenuation.(2)Aerobic exercise and supplementation of oyster peptide can promote testosterone secretion in PADAM rats,and have a significant effect on controlling the occurrence of PADAM;at the same time,it can effectively improve skeletal muscle protein synthesis ability,prevent skeletal muscle attenuation caused by PADAM formation,and aerobic Exercise combined with oyster peptide supplementation is better.(3)The content of IGF-1 decreased and the content of MSTN increased,which led to the obstruction of mTOR signaling pathway,decreased phosphorylation of mTOR and Akt,enhanced expression of 4EBP-1 in downstream,and decreased expression of P70S6K and eEF2,thus inhibiting skeletal muscle protein synthesis leads to skeletal muscle attenuation.(4)Aerobic exercise and supplementation of oyster peptide can activate the mTOR pathway throughIGF-1?MATN,transmit the activation signal to the downstream target protein,promote the translation of skeletal muscle protein,thereby enhancing protein expression,delaying skeletal muscle attenuation and delaying aging.The role of aerobic exercise combined with oyster peptide supplementation is better.