Nerve regeneration and pharmacological suppression of the scar reaction at the suture site. An experimental study on the effect of estrogen-progesterone, methylprednisolone-acetate and cis-hydroxyproline in rat sciatic nerve.

Pharmacological suppression of the scar reaction was tested as a possible method for improving axonal regeneration after transection and suture of the sciatic nerve of rats. The animals in the experimental groups were systemically treated post-operatively with estrogen-progesterone, methylprednisolone-acetate (Depomedrone) or cis-hydroxyproline. Only in the cis-hydroxyproline treated animals was there a tendency towards a decrease in fibroblastic activity at the suture site after 4 weeks. However, there was no difference in the growth of axons to the distal nerve segment after pharmacological treatment as compared to non-treated animals, when tested 12 weeks post-operatively. The motor nerve conduction velocity was however significantly greater in both the cis-hydroxyproline and the methylprednisolone-acetate groups as compared with the estrogen-progesterone and the control groups. In conclusion, cis-hydroxyproline and also methylprednisolone-acetate may improve the function of regenerating peripheral nerve, while estrogen-progesterone does not seem to have this effect.