COMPARISON OF BASIC FIBROBLAST GROWTH-FACTOR IN X-LINKED DYSTROPHIN-DEFICIENT MYOPATHIES OF HUMAN, DOG AND MOUSE

Binding of polyclonal antibodies specific for bFGF was examined in tis sue sections of myopathic and normal muscles from humans, dogs and mic e. The proposal tested was that differences in the amount or distribut ion of bFGF in muslces of the 3 species, might correlate with the limi ted muscle regeneration seen in humans and dogs afflicted with x-linke d muscular dystrophy, in contrast with the sustained new muscle format ion in mdx mice with the homologous myopathy. There was a striking dif ference between the species in the binding of bFGF antibodies to extra cellular matrix, particularly at the periphery of myofibres; binding w as pronounced in mouse but weak or absent in human and dog muscle. Bin ding to muscle nuclei and sarcoplasm was also stronger in mice than in humans and dogs, and in all species was more pronounced in foetal tha n adult muscle. Increased binding of bFGF antibodies was seen in damag ed and regenerating muscle cells in all myopathic specimens where thes e were present. This was associated with the regenerative process rath er than with myopathy, as a similar pattern of bFGF expression was see n in mouse muscle regenerating after experimental crush injury. The hi gher extracellular staining for bFGF around the periphery of mouse myo fibres correlated with the successful muscle regeneration in dystrophi c mice. Results suggest that bFGF at the fibre periphery might stimula te a local increase in the numbers of muscle precursor cells which can respond to injury in the mdx mouse.