Experimental Study On The Peripheral Nerve Regeneration Promoted By Control Releasing FK506

Objective:To discuss the morphologic effects and function of regenerative nerve fibres affected by control releasing FK506.Methods:Ninety-six Sprague-Dawley rats with10mm gap of sciatic nerve were randomly divided into two groups which had been bridged with the new double channel nerve conduit of fusiform shape, Each group contained forty-eight animals, in the first group,100u1of chitin for medical use was injected into the conduit, in the second group, the two branches of the conduit contained100μl of the chitin and5μl FK506(B1)or physiologic saline(B2) At8,12and16week after operation,we evaluated the morphology of regenerative nerve by Homes silver staining and hematoxylin-eosin staining, the number of myelinated fibre and the myelin sheath of regenerative nerve were counted bytransmission electron microscope(TEM) at16week after operation..We also evaluated the axoplasmic transport of regenerative nerve in the two branch channels with Horseradish peroxidase(HRP) and Nuclear yellow(NY) and electrophysiologic effects were evaluated by detect compound muscle active potential(CMAP) or cortical somatosensory evoked potential(CSEP) and nerve conduction velocity (NCV) at12and16week after operation.Results:There were not significant differences of the regenerative nerve fibres between two channels in group A,But in group B1, the number of the regenerative fibres is much more than the one in group B1, The number of motor and sensitive fibres of regenerative nerve in group B1was much more than the nul6mber in group B2(p<0.05). There were more and well-arranged regenerative fibres in branch contained the FK506, When the tracing substance of HRP and NY were injected to the regenerative nerve in the branch contained FK506, the positive neurons in the spine cord was much more and densely distribute. The latency of CMAP and CSEP is shorter in group B2than the one in group B1, but its amplitude was higher.there were significant difference between them (p<0.05). in group B1, the number of myelinated fibre of regenerative nerve of FK506branch is much more, and the myelin sheath is also thicker. Both the myelinated fibre and unmyelinated fibres and area of unmyelinated fibre in the FK506lateral branch incresed.The diameter of axon and the area of myelinated fibre of FK506lateral branch is larger than the ones of group B2(p<0.05) Conclusion:The morphologic effects and function of regenerative nerve fibres could be significantly promoted by control releasing FK506.