HISTOLOGIC EVIDENCE FOR A TOXIC POLYNEUROPATHY DUE TO EXPOSURE TO 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) IN RATS

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a considerable environme ntal hazard in industrial societies. Its toxic effects on animals and humans are numerous, but little is known about its neurotoxicity. We s tudied the neurotoxic effects of TCDD in 80 male, adult Wistar rats. T he substance was dissolved in com oil and a single dose injected intra peritoneally (8.8 mug, 6.6 mug, 4.4 mug or 2.2 mug/kg). Neurophysiolog ical examinations proved a dose-related, statistically significant slo wing of sensory and motor conduction velocities. Ten months after the application of TCDD peripheral nerves showed a progressive, and proxim ally accentuated neuropathy. The extent of changes, however, differed remarkably between individual animals. Our data indicate that TCDD cau sed a toxic polyneuropathy in rats.