Tetrachloroethylene: levels of DNA and S-100 in the gerbil CNS after chronic exposure.

Concentrations of the astroglial protein S-100, DNA and protein were studied in different regions of the gerbil CNS after chronic tetrachloroethylene exposure. The animals were exposed by continuous inhalation at 60 or 320 ppm for three months, followed by a four month solvent-free period. Increased concentrations of S-100, indicative of astroglial hypertrophy and/or proliferation, were found not only in the hippocampus and in the cerebral occipital cortex, but also in the cerebellar areas. In the frontal cerebral cortex, decreased S-100 and DNA concentrations were found to be concomitant with a decreased wet weight of the area, suggesting an atrophy which also affects the astroglial cells. This atrophy also is reflected in decreased DNA concentrations found after exposure at 60 ppm in this region of the brain. These results are consistent with the observation that tetrachloroethylene is a potent neurotoxin, as changes in the gerbil brain were found even at exposure levels as low as 60 ppm.