EFFECTS OF ANTIOXIDANT TREATMENT ON SCIATIC-NERVE DYSFUNCTION IN STREPTOZOTOCIN-DIABETIC RATS - COMPARISON WITH ESSENTIAL FATTY-ACIDS

In Study 1, the effects of treatment of streptozotocin-diabetic rats w ith the antioxidants, probucol or vitamin E were compared. Untreated d iabetic rats showed a reduction of 45% (p < 0.01) in nerve laser Doppl er flux, which was used as an index of nerve blood flow. In diabetic r ats treated with either probucol or vitamin E nerve Doppler flux was r educed by only 13 or 16%, respectively (p < 0.01 for either compared t o untreated diabetic rats). A second study examined the effects of tre atment with evening primrose oil either alone or in combination with p robucol. Reduced nerve Doppler flux was reproduced in untreated diabet ic rats (47%; p < 0.01). In parallel diabetic groups, nerve Doppler fl ux was reduced by only 14% with evening primrose oil alone and by 8% w ith evening primrose oil plus probucol (both p < 0.01 vs untreated dia betic rats). Both treatments were also associated with marked attenuat ion of motor and sensory nerve conduction velocity deficits. Measureme nts on plasma from rats showed normalisation of triglyceride levels by probucol treatment without an effect on those of cholesterol in Study 1. In Study 2, the converse was true for evening primrose oil treatme nt, whilst the combined treatment lowered both plasma triglycerides an d cholesterol. This work indicates similar effects of antioxidants and evening primrose oil against reduced nerve Doppler flux and conductio n velocity in diabetic rats, with dissimilar actions on plasma triglyc erides and cholesterol.