[Effects of substituted dextran on reinnervation of a skeletal muscle in adult rats during regeneration].

RGTA11 is a chemically substituted dextran that mimics some of the properties of heparin or heparan sulphates towards heparin binding growth factors as well as inhibits some heparin binding proteases. In vivo RGTA11 has been shown to enhance muscle regeneration after crush. We now present evidence that RGTA11 can alos favour reinnervation of fast (EDL) as well as slow (soleus) crushed muscles. Both types of muscles were injected with RGTA11 after crushing and nerve cutting. In EDL muscles, after 16 days, motor end plates were more rapidly reformed and choline acetyl-transferase activity was 2 fold higher than in controls. In soleus muscles, after 16 days, motor end plates were reformed at normal size while controls were on average 30% smaller, the 16S form of acetyl-cholinesterase and choline acetyl-transferase activity were twice those of non injected regenerating controls. In conclusion, RGTA11 favours axonal growth and synaptic differentiation, allowing a more rapid reinnervation and maturation of the regenerated fibers. RGTA may present a new family of drugs against neuromuscular degenerescence.