The Experimental Study on Central & Peripheral Nerve Tissue Responses to the Chymopapain in Rabbits

The treatment of herniated lumbar disc has been a challenging problem in spite of various methods of treatments such as conservative, chymopapain injection, percutaneous automated nucleotome method and surgical removeal of discs. Among the above listed treatment, Smith and Brown reported the clinical experience by way of intradiscal injection of chymopapain with beneficial result and clinical reports followed thereafter.

On the other hand, the serious neural adverse effects were reported by Smith laboratories since the clinical application of chymopapain such as transverse myelitis, paralysis, seizures and hemiplegia which is not fully clarified but may be due to chymopapain itself and improper technique. This study was carried out to clarify the effect of chymopapain on the spinal cord and peripheral nerves by way of application topically in rabbits.

The results were as follows :

1) There were no abnormal gross or histological findings when the chymopapain was spread around the sciatic nerve and spinal cord extradurally.

2) In the group of the chymopapain injected into the sciatic nerve sheath, there was immediate nerve paralysis and severe necrosis of the axon. But the schwann's sheath was intact and no hemorrhage was observed.

3) In the group of intradural chymopapain injection, there was massive hemorrhage, perivascular neutrophil infiltration and necrosis of the gray mater of spinal cord.

In conclusion with this experimental study, the chymopapain induced peripheral neuropathy followed by axonal necrosis when injected into peripheral nerve. The central neuropathy was developed with hemorrhage and necrosis of the gray mater of the cord when the chymopapain injected intradurally.