RESUMEN
Objective To investigate the pathological and electro-physiological process of terminal sprouting after muscle injection of Botulinum toxin type A(BTXA) in rats. Methods Sprague-Dawley rats were randomly divided into a BTXA group and a control group. Five unit of BTXA was injected into the right gastrocnemius of the rats in BTXA group, instead of 0.9% saline in the control group. The morphologic axon analysis and SFEMG (mean consecutive difference and fiber density) were measured at 1,4,8,12 week after injection. Results The mean consecutive difference was prolonged in 1-4 week, and got better at 8 week, recovered at 12 week. It was revealed of the recovery of neuromuscular junction at 12 week after BTXA injection. The results of fiber density and morphologic axon analysis demonstrated terminal sprouting after injection of BTXA. Conclusion Motor nerve terminal sprouting could appear after BTXA injection and the function of neuromuscular junction could become recovered at 12 week.