PHOTOCHEMICALLY INDUCED ISCHEMIC LESION OF THE RAT SCIATIC-NERVE - A NOVEL METHOD PROVIDING HIGH-INCIDENCE OF MONONEUROPATHY

THE incidence of behavioural signs of mononeuropathy in rats subjected to chronic constriction injury (CCI) of the sciatic nerve is unpredic table and often low. In the present study, an ischaemic lesion of the rat sciatic nerve was induced photochemically using a low power laser. In these rats tactile allodynia developed with a considerably greater incidence (95%) than in control rats subjected to CCI (45%). The allo dynia lasted longer and was more prominent. Responses to thermal stimu lation did not markedly differ between the two groups. The ischaemic l esions displayed marked degeneration, particularly of large myelinated fibres. The results suggest that laser irradiation of a peripheral ne rve inducing a local photochemical reaction followed by Wallerian dege neration may be a convenient and reproducible experimental method of p roducing signs of peripheral mononeuropathy.