An Experimental Study Of Chondroitinase ABC (chABC) On Sciatic Nerve Regeneration In Rats

PurposesPeripheral nerve regeneration and functional recovery are often incomplete after nerve injury. Regenerating nerve sprouts encounter both growthpromoting and growth-inhibiting molecules at the repair site.The best known inhibitory molecules are the chondroitin sulfate proteoglycans (CSPGs) that contain glycosaminoglycan (GAG) side-chains. This reaction can be reduced by chondroitinase ABC, since the enzyme digests chondroitin GAG and removes the inhibitory effect of CSPGs.The aim of this study was to determine whether chondroitinase ABC injection at the lesion site could be effective in promoting sciatic nerve regeneration.MethodsSeventy-two SD rats were randomly divided into three groups, twenty-four rats in each group.The sciatic nerves on bilateral of all rats were exposed and a 10mm-long segment were removed and bridged with chitin chamber about 20μl. ChABC microspheres was injected into the chamber in group A, equal quantity of excipients was injected into the chamber in group B, equal quantity of isotonic saline was injected into the chamber in group C. The sciatic nerve was re-exposed through the same incision at four,eight weeks post-operatively, nerve conduction velocity of regenerative sciatic nerve were monitored.The Loyez's neural staining and s-100 immunohistochemical staining analysis of the specimens to assess regeneration of nerves. Using Image-Pro Plus 6.0 image analysis system for analysis. Results1 Histological observation indicated that the regenerated nerves passed through the nerve regeneration chamber and there were regenerated blood vessels formation in three groups at 4 and 8 weeks after operation.2 The electrophysiological examination of nerve regeneration showed that velocity in group A was higher than the group B and C,the difference was of statistical significance (p<0.05). There was no statistical difference betwen group B and C (p>0.05).3 S-100 immunohistochemistry staining showed that the S-100 positive cells were more evenly distributed in regenerated nerves. The quantity of positive cells in group A was more than the group B and C,the difference was of statistical significance (p<0.05). There was no statistical difference betwen the group B and C (p>0.05).4 Loyez's neural staining showed that the quantity of nerve fibers in group A was higher than group B and C,the difference was of statistical significance (p<0.05). There was no ststictical difference betwen the group B and C (p>0.05).Conclusions1 The chitin of nerve conduits filled with chABC can enhance the nerve regeneration.2 Chondroitinase ABC does not influence the proliferation of Schwann cells after sciatic nerve injury.3 Chondroitinase ABC can promote the injured sciatic nerve conduction, axonal regeneration and functional recovery.