Histochemical and neurophysiological studies of autotransplanted cat muscle.

Free autologous transplants of previously denervated whole muscles in adult cats were studied with histochemical and electromyographical methods. The transplants were placed in contact with normal intercostal muscles in intercostal spaces and removed at intervals from 5 days to 44 weeks after transplantation. Normal muscles as well as transplanted muscles without previous denervation and muscles denervated and left in situ were also studied.. The fibres of the previously denervated grafts survived the first avascular period, but a de-differentiation of enzymatic characteristics of the red and white fibres occurred and endured during the first 6 weeks after grafting. The first signs of reinnervation could be identified with electromyography after 4 weeks and with histochemical techniques after 6. Reinnervation of most of the fibres of the transplants was completed about 14-18 weeks after grafting. No fibrillations were then found electromyographically and in the histochemical preparations most fibres had attained near-normal staining characteristics. Type grouping was apparent but less pronounced than reported after reinnervation through the motor nerve. There was conclusive evidence that previously denervated muscles survived transplantation and became structurally and enzymatically mature whereas muscles transplanted without previous denervation undergo extensive fibrotic changes.