Inhibition of myotube formation by paraquat in the myoblast cell line C2C12.

Paraquat (PQ) is one of the most frequently used pesticides in worldwide. In most countries, PQ is used without restrictions. To investigate the effect of PQ on myogenesis, cultures of C2C12, a useful model to study differentiation of myoblasts into myotubes, were exposed to various concentrations of PQ. Myotube formation did not occur in the presence of 50 µM PQ. Although cell death was not observed at this concentration, growth inhibition was evident in the growth medium. Production of myosin heavy chain, a myogenesis marker protein, decreased dose dependently with the concentration of PQ, which was added to the C2C12 cell culture during differentiation. Inhibition of myogenesis by PQ was not reversed by the addition of ascorbic acid. These results show that PQ is a strong inhibitor of muscle differentiation in vitro.