Effect Of Unfed, Dexamethasone And LED On Protein Content Of Differentiated C2C12 Myoblast

Eccentric exercise often lead to Delayed onset muscle soreness(DOMS). The mechanism and theraphy of DOMS studed most. Among the three step (Z-disc split, degradation of damaged protein, protein synthesization )of DOMS, degradation of damaged protein through Ubiquitin-Proteasome Pathway (UPP) is the step that limit the progress rate of DOMS. And what contribute most to the UPP depended protein degradation is glucocorticoid pathway.Object: we replicate a protein degradation model in vitro via treating the differentiated C2C12 myoblast with dexamethason(DEX). And we expose the model to LED irradiation to search what effect it will have on protein degradation.Metherd: Test 1: C2C12 were allowed to differentiate for 4 days. Then treated with for different way. Beginning at day 4 Normal cells were fed everyday, Unfed cells were not fed, DEX cells were fed everyday by the medium including 100nM dexamethasone, UnfedDEX cells were not fed after fed by the medium including lOOnM dexamethasone in day 4. from day 5 after differentiation protein content were determined everyday for 4 days. Test 2: expose the model of Test 1 to LED irradiation(60mA,650±17nm, 15min/day) for 2 days. Dose were 207 mJ/cm~2, 435.6 mJ/cm~2, 662.4 mJ/cm~2, 1194.3 mJ/cm~2 respectively. protein content were determined on day 6.Result: Test 1: Protein content of Unfed, DEX and UnfedDEX cells were all significantly lower than that of Normal cells(P<0.01), Protein content of DEX and UnfedDEX cells were both significantly lower than that of Unfed cells(P<0.01). There was no significant different between DEX and UnfedDEX cells. Test 2: Only 2 days 662.4 mJ/cm~2 LED irradiation make the protein content significantly higher then that of DEX cells(P<0.01). 207 mJ/cm~2, 435.6 mJ/cm~2, 1194.3 mJ/cm~2 LED irradiation have no effect on protein content of the DEX model.Conclusion: lOOnM dexamethasone can significantly accelerate Protein degradation of the differentiated C2C12 myoblast, it was similar with the condition of muscle atrophy in vivo. The stimulative effect of dexamethasone on Protein degradation was significantly inhibited by 2 days of 662.4 mJ/cm~2 LED irradiation.