Masking of a dystrophic symptom in genotypically dystrophic-dwarf mice.

In muscular dystrophic mice, the foreleg seemed to be almost normal in function, whereas the hindleg showed a characteristic dragging symptom on and after two weeks of age. We reported that the apparently normal foreleg was also affected by one month of age.lo~ Thus, the foreleg muscles were essentially similar to the dragging hindleg muscles2>,3) in their increased collagen content,9~ the level of protease activity4~ and the histo-pathological changes. Also the growth of the fore-and hindleg muscles was arrested at about one month of age, and the drastic changes in the apparent volume per muscle cell which would occur on and after 10 days of age in normal development were not observable in the dystrophic mice.8