NEUROELECTROPHYSIOLOGICAL ABNORMALITIES ARE RELATED TO METABOLIC AND ADVANCED NONENZYMATIC GLYCATION CHANGES IN PROSPECTIVELY EVALUATED DIABETIC SPRAGUE-DAWLEY RATS

In order to sequentially explore central (CNS) and peripheral (PNS) ne rvous system abnormalities in experimental diabetes mellitus, neuroele ctrophysiological and nervous protein biochemical changes were investi gated in streptozotocin diabetic Sprague-Dawley rats after 1.5, 3, 6 a nd 12 months from induction of diabetes, Visual (VEP), brainstem-audit ory (BAEP) and somatosensory (SEP) evoked potentials were evaluated in control and diabetic rats. Advanced glycation end-product (AGE) level s mere measured by spectrofluorimetry in protein extracts from central and peripheral nervous tissue samples, Mean VEP (Pi wave) and BAEP (w aves I, IP and III) latencies were increased whereas SEP (Tarsus-L6, L 6-Cortex and T6-Cortex) conduction/propagation velocities were reduced in diabetic rats at all times (p<0.05 to p<0.0001), the alterations b eing already present after 1.5 months from diabetes induction, Similar ly, AGE levels in diabetic rat protein extracts were higher than in co ntrol animals, the differences becoming statistically significant with the progression of the disease, When metabolic, neuroelectrophysiolog ical and biochemical alterations were evaluated with time in diabetic rats, a rapid initial change was observed, and followed, in the case o f the metabolic control, by steadily abnormal values and as well as, i n the case of the electrophysiological and biochemical values, by a co ntinuous slow worsening, Finally, a statistically significant associat ion was found between electrophysiological and biochemical parameters, Thus CNS, but more so PNS, neuroelectrophysiological abnormalities an d enhanced nervous protein AGE levels appear relatively early after di abetes induction and, in the presence of an altered metabolic status, are correlated and worsen over time. (C) 1997, Editrice Kurtis.