Abstract:

BACKGROUND: Duchenne’s muscular dystrophy (DMD) is a fatal recessive X-linked form of muscular dystrophy characterized by progressive muscular degeneration, and there is no cure for DMD currently. Stem cell transplantation may provide us with a creative perspective. But the myogenic differentiation rate of transplanted cells is quite low in skeletal muscle.
OBJECTIVE: The differences of myogenic, adipogenic and osteogenic gene expression levels in skeletal muscle between mdx mice and C57BL/6J mice were compared, with the purpose of investigating the underlying mechanism of pathological changes in skeletal muscle from mdx mice.
METHODS: Frozen sections of skeletal muscle from mdx and C57BL/6J mice were prepared, stained with hematoxylin-eosin staining and Vonkossa staining. The morphological changes of the muscles were observed under microscope. Additionally, total RNA of skeletal muscle from mdx and C57BL/6J mice was extracted, reversed, and the expression levels of myogenic, adipogenic and osteogenic characteristic genes were examined by real-time PCR.
RESULTS AND CONCLUSION: Necrosis and regeneration were found in skeletal muscles of mdx mice, and mild adipose hyperplasia and fibrous connective tissue hyperplasia were also observed. Moreover, calcium deposition nodules were easily detected by Vonkossa staining. The form of skeletal muscle cells from C57 mice was clear, and the nuclei were located in the cell periphery. Osteogenic and adipogenic gene expressions of skeletal muscle from mdx mice were elevated to a certain degree by real-time PCR (P < 0.05), compared with C57 mice, whereas myogenic gene expression was decreased (P < 0.05). The reason why adipocyte and osteoblast in skeletal muscle of mdx mice overgrew may be due to degeneration and necrosis of skeletal muscle which caused by dystrophin gene deletion, and it differentiates into osteoblasts and adipocytes instead of myoblasts.