Effect of Neriifolin on Differentiation of C2C12 and Extraocular Muscle Satellite Cells

Paralytic strabismus involves a functional loss of extraocular muscles resulting from muscular or neuronal disorders. Currently, only a limited number of drugs are available for functional repair of extraocular muscles. Here, we investigated the effects of a novel drug, Neriifolin, on the differentiation of extraocular muscles as assessed in both in vivo and in vitro models. The effect of neriifolin on C2C12 cells was examined in vitro as evaluated with use of apoptosis, reactive oxygen species (ROS), and cell viability assays. Then, both in vivo and in vitro effects of this drug were examined on the differentiation of C2C12 and satellite cells within extraocular muscles in rabbits. For these latter experiments, RT-PCR and Western blot assays were used to determine expression levels of markers for myogenic differentiation. With use of neriifolin concentrations ranging from 0 to 10 mu M, no effects were observed upon cell apoptosis, ROS, and cell cycle in C2C12 cells. Based on MTT assay results, neriifolin was shown to increase C2C12 cell proliferation. Moreover, neriifolin promoted the differentiation of C2C12 and satellite cells within extraocular muscles in rabbits, which were verified as based on cell morphology and expression levels of mRNA and protein markers of myogenic differentiation. Finally, neriifolin treatment also increased gene expressions of Myh3, Myog, and MCK. The capacity for Neriifolin to upgrade the differ entiation of both C2C12 and satellite cells within extraocular muscles in rabbits at concentrations producing no adverse effects suggest that this drug may provide a safe and effective means to promote repair of damaged extraocular muscles.