OBJECTIVETo observe the influence of combined injection with human interferon (hlFNgamma) and human insulin-link growth factor-1 (hIGF-1) on regeneration and fibrosis of skeletal muscle after acute contusion.

METHODSA standard contusion model was reproduced at the right gastrocnemius in 64 male mice of 7 to 12 weeks. All the mice were randomly divided into 4 groups, such as group A (injection with hIFNgamma), group B (injection with hIGF-1), group C (injection with hIGF-1 and hIFNgamma), and group D (injection with physiological saline as control). All injections were introduced on day 10 after injury at local injured gastrocnemius. Before intervention (7 d following injury), and 4 d, 18 d, 32 d after intervention, the local injured gastrocnemius were harvested from 4 mice of each group. Then the expression of MHC- II b and vimentin was detected by real time PCR and immunohistochemistry techniques.

RESULTS(1) At the each time following intervention, the expression of MHC-II b mRNA and protein in local injured muscle of group B and C were significantly higher than those of group A and D. (2) After intervention,the expression of vimentin mRNA and protein in local injured muscle of group A, group B, and group C were more inhibited than those of group D. The inhibition of vimentin expression in group A and C was significant.

CONCLUSIONIt is indicated that injection of hIGF-1 into the injured skeletal muscle following acute contusion could enhance muscle regeneration,and inhibit fibrosis to some extent. (2) It is identified that hIFNgamma injected into injured muscle has the effect of anti-fibrosis, which is more significant than that of hIGF-1. (3) Combined injection with hIGF-1 and hIFNgamma could improve muscle regeneration and inhibit fibrosis simultaneously, and promote the healing of injured muscle.