Abstract: To observe the effect of the mice which were injected by MSTN genetically engineered proteins for studying the function of the MSTN. Fifty mice(25 female and 25 male rats) were divided into two groups, experimental group and control group both included male and femle rats. The control groups were injected normal saline(NS) and the experimental groups were injected MSTN proteins. Weighing respectively every other day for 3 months. The mice were executed after the test period, we collected their hamstrings, through paraffin section and dipping segregation methods, observed the mice’s muscle fiber diameter. Results indicated that the recombinant Tibetan sheep myostatin C-domain can inhibit muscle growth in the early time of mice(about 37 to 45 days old). When the antibodies to be produced in the blood of mice, the function of recombinant Tibetan sheep myostatin C-domain gradually be weakened. The recombinant Tibetan sheep myostatin C-domain can increase muscle fiber cross sectional area and muscle fiber diameter of mice.

Key words: Tibetan sheep; MSTN; mice; paraffin section; muscle fiber