Characterization of Myostain (MSTN) and Myogenic Differentiation Antigen (MyoD) and the Effect of Dexamethasone on Their Expression in Large-Scale Loach Paramisgurnus dabryanus.

Myostatin (MSTN) and myogenic differentiation antigen (MyoD) play an essential role in specification and differentiation of skeletal muscle. However, the role of stress in the regulation of MyoD and MSTN has not been fully revealed and more evidence should be provided. Here, we reported the cloning and expressional analyses of MSTN and MyoD in Large-scale Loach Paramisgurnus dabryanus (hereafter PdMSTN and PdMyoD). Injecting individuals with 0, 60, 600, and 1,200 µg/kg dexamethasone (DXM) for five consecutive days resulted in a dose-dependent change of PdMSTN and PdMyoD expression. The expression of PdMSTN was upregulated with increasing DXM concentrations, while PdMyoD expression was downregulated. The changes in the expression of these genes at different time points for 10 consecutive days were studied after individuals were treated with 600 µg/kg DXM. Compared with the control group, PdMSTN expression decreased and PdMyoD expression increased before 12 h, and both PdMSTN and PdMyoD expression levels increased at 24 h, which was significantly higher than those in control group. At a prolonged treatment of 5-10 d, expression levels of PdMSTN and PdMyoD had significantly reduced. The results indicate that both PdMyoD and PdMSTN are involved in DXM-induced stress in Large-scale Loach.