Glycerol induces early fibrosis in regenerating rat skeletal muscle.

Glycerol has been recently used to induce muscle adiposity in mice. However, its effects on the rat muscles have not been investigated previously. Therefore, we investigated the regeneration outcomes of rat muscles following glycerol-induced injury at different time points. Glycerol injection induced myofiber degeneration with extensive inflammatory infiltration on day 4 followed by appearance of regenerating myotubes on day 7 after injury without adipocyte infiltration. Meanwhile, a significant collagen deposition at early stage of regeneration that increased together with persistent inflammatory infiltration up to day 14 after injury indicates impaired regeneration. In conclusion, glycerol injury in rats is more suitable as a fibrosis-inducing model than in mice due to earlier and higher accumulation of fibrous tissue with lacking adipogenesis.