[Experimental study of treating Duchenne muscular dystrophy with myoblast transplantation].

Objective: To investigate the effect of myoblast transplantation on duchenne muscular dystrophy (DMD) and to explore the method and feasibility of applying gene therapy to DMD.

Methods: Myoblast of C57/BL10 mice were cultured using multiple-step enzyme digestion method and differential velocity adherent technique. The morphology of the cells was observed with inverted phase contrast microscope. The cells at passage 4 were labeled with 5-BrdU. Twenty-four DMD model mice (mdx mice: aged 4-6 weeks, male, 13.8-24.6 g) were randomly divided into two groups (n = 12 per group): group A, 1 x 10(6)/mL labeled myoblast were injected via ven caudalis twice at an interval of 2 weeks; group B: 1 mL DMEM/F12 was injected in the same manner serving as a control group. The mice were killed 4 weeks after operation and the motor ability of the mice was detected by one-time exhaustive swimming before their death. HE staining and immunohistochemistry staining observation for 5-BrdU, desmin, and dystrophin (Dys) were preformed, and the imaging analysis was conducted.

Results: The primary myoblast could be sub-cultured 5-7 days after culture, providing stable passage and sufficient cells. The time of one-time exhaustive swimming was (60.72 +/- 5.76) minutes in group A and (47.77 +/- 5.40) minutes in group B, there was significant significance between two groups (P < 0.01). At 4 weeks after injection, HE staining showed that in group A, there were round and transparent-stained myocytes and the percentage of centrally nucleated fibers (CNF) was 67%; while in group B, there were uneven muscle fiber with such pathological changes as hypertrophia, atrophia, degeneration, and necrosis, and the percentage of CNF was above 80%. Immunohistochemistry staining revealed that the expression of 5-BrdU, desmin, and Dys was positive in group A; while in group B, those expressions were little or negative. Image analysis result displayed that integral absorbency (IA) value of desmin was 489.70 +/- 451.83 in group A and 71.15 +/- 61.14 in group B (P < 0.05) and the ratio of positive area to the total vision area was 0.3143 +/- 0.1973 in group A and 0.1028 +/- 0.0628 in group B (P < 0.05); the Dys IA value was 5424.64 +/- 2658.01 in group A and 902.12 +/- 593.51 in group B (P > 0.05) and the ratio of positive area to the total vision area was 0.3237 +/- 0.1177 in group A and 0.0352 +/- 0.0329 in group B (P < 0.05).

Conclusion: Myoblast transplantation has certain therapeutic effect on DMD of mice.