Changes in fibre type, metabolic character and acetylcholinesterase forms in rabbit skeletal muscle following stretch...

Several trials have been made to reconstruct the neoanal sphincter using continuous electrical stimulation of the rotative gracilis muscle flap, with a view to improving Pickrell's technique. To detect muscle alterations with this technique, the gracilis of the rabbit was transposed on the external side of the thigh, either to be made into a rotative muscle flap, or to be stimulated (10 Hz). Our data show that the simple transposition of the muscle did not significantly affect its fibre type composition. On the contrary, slow-twitch fibres were predominant in the transposed-stimulated gracilis muscle. The control gracilis muscle presented a glycolytic metabolism, it developed an intermediate metabolism after transposition with a predominant oxidative metabolism after stimulation. The AChE molecular form pattern of the control gracilis was characteristic of fast-twitch rabbit muscle. Surprisingly, the AChE polymorphism of transposed and transposed-stimulated gracilis muscles did not differ. They were both similar to slow-twitch rabbit muscles. Taken together, these data could explain the uncertain clinical results after Pickrell's procedure and should foster the development of electrically stimulated neoanal sphincter.