INTRASPINAL INJECTION OF EMBRYONIC NEURONS MAINTAINS MUSCLE PHENOTYPEIN ADULT CHRONIC SPINAL RATS

A suspension of monoaminergic embryonic neurons was transplanted into the spinal cord of paraplegic rats, Enzyme histochemical, morphometric , and biochemical analyses of the hindlimb musculature were carried ou t 2-5 months later to determine the consequences on muscle atrophy and muscle phenotypes which were compared in three groups of rats: intact , spinalized, and spinalized and transplanted with embryonic cells, Ou r results indicate that this transplantation does not prevent muscular atrophy, which appears highly dependent on the level of muscular acti vity, but partially maintains the slow phenotype, especially in the so leus muscle, We conclude that fiber phenotypes are not determined by t he level of muscular activity alone but are also dependent on putative trophic factors synthesized by motoneurones. (C) 1996 Wiley-Liss, Inc .