Abstract

This study investigated the effects of a CoCl 2 -simulated hypoxic environment on the muscle fiber switching signaling pathways calcineurin A/nuclear factor of activated T cells cytoplasmic 1 (CnA/NFATc1) and myostatin . In this study, C2C12 muscle cells were cultured in vitro under CoCl 2 -simulated chemical hypoxic conditions, the expression levels of CnA and myostatin were detected through qRT-PCR and Western blot analyses, and a positioning study of NFATc1 was carried out by immunofluorescence labeling. Results showed that CoCl 2 treatment significantly increased the expression levels of CnA and myostatin. Moreover, the position of NFATc1 expression changed; actually, its expression in the nucleus considerably increased. Furthermore, CoCl 2 -induced hypoxia inhibited the differentiation of C2C12 cells and reduced the expression levels of many slow- and fast-twitch muscles marker genes, but immunofluorescence staining results showed that the proportion of MyHC I type muscle fiber increased after CoCl 2 treatment. The hypoxic environment simulated by CoCl 2 can activate the signaling pathways CnA/NFATc1 and myostatin and increases the proportion of MyHC I type muscle fibers.