[The changes of the muscular fiber phynotype at different condition of nerve injury].

ABSTRACT

OBJECTIVE: To observe the change of the muscular fiber phynotype at different condition of nerve injury. METHODS: Rabbits were used as an animal model in this study. The trigeminus and facial nerves of the animal were simultaneously severed (group 1) or only the latter was severed (group 2). The morphologic change of the muscular fibers was observed with histochemical methods; the tension of contraction and the threshold value of electrical stimulation were observed with electrical physiological methods. RESULTS: Trigeminus nerve play an important role in delaying muscular atrophy after facial nerve was severed. The atrophy degree of type II a and II b muscular fibers was less in group 2 than that in group 1. The change of type 1 muscular fibers was not affected by trigeminus nerve. New muscular fibers emerged in group 2. The tension of contraction and the threshold value of electrical stimulation were better in group 2 than that of in group 1. CONCLUSIONS: Sensory nerve could delay muscle atrophy after denervation. Sensory nerve should be repaired simultaneously when the motor nerve was sutured. The results of this study would facilitate clinical treatment for facial palsy.