THE EXOGENOUS ADMINISTRATION OF BASIC FIBROBLAST GROWTH-FACTOR TO REGENERATING SKELETAL-MUSCLE IN MICE DOES NOT ENHANCE THE PROCESS OF REGENERATION

The effects, in vivo, of the exogenous administration of bFGF on myoge nesis of regenerating skeletal muscle was assessed either morphometric ally or autoradiographically in three separate models of muscle injury in mice: crush-injured, denervated, and dystrophic (mdx) muscles. The bFGF was administered at various doses and different time schedules, sometimes in combination with heparin, into injured tibialis anterior muscles of mice. Delivery of the bFGF was either by direct intramuscul ar injection or by the sustained release from polymers (Hydron or Elva x) implanted into the muscles. The bioactivity of bFGF was confirmed i n vitro by measuring its ability to stimulate the proliferation of BAL B/c-3T3 fibroblasts and muscle precursor cell lines. The ability of bF GF to stimulate angiogenesis in vivo was confirmed by the implantation of controlled-release polymers containing bFGF into the normally avas cular cornea of rats. No measurable effect of bFGF was seen in any of the models of skeletal muscle injury under these experimental conditio ns, indicating that the availability of biologically active bFGF is no t a limiting factor in the regeneration of skeletal muscle following i njury.