Electroretinal responses are modified by chronic exposure to trichloroethylene

Using an inhalation chamber, New Zealand albino rabbits were exposed to 350 ppm (n = 6) and 700 ppm (n = 8) of trichloroethylene (TRI) 4 hrs/day, 4 days/week for 12 weeks. Electroretinograms (ERG) and oscillatory potentials (OPs) were recorded weekly under mesopic conditions. Blood samples were also collected weekly to determine the concentration of TRI and its main metabolites. Recordings from the 350 and 700 ppm exposed groups showed a significant (p < 0.01) increase in the amplitude of the a- and b-waves (ERG), while the amplitude of the OPs was significantly (p < 0.01) decreased at 350 ppm and increased at 700 ppm. These electroretinal changes were reversed to the baseline value within six weeks after the inhalation stopped. The observed variations in a-wave and OP amplitudes were related to plasmatic level of trichloroethanol, while the effects on the b-wave were related to the blood level of TRI. These results confirm the neuro-ophthalmotoxicity of TRI and support the hypothesis that trichloroethanol is the major neurotoxic metabolite of TRI.