Total number and mean cell volume of neocortical neurons in rats exposed to 2,5-hexanedione with and without acetone

The toxicological effects of 2,5-hexanedione (2,5-HD) alone and combined with acetone on the number and size of neurons in the cerebral cortex of rats were evaluated with stereological techniques. Thirty rats were equally divided into three groups: One control, one receiving 0.5% 2,5-HD, and one receiving 0.5% 2,5-HD and 0.5% acetone in the drinking water for seven weeks. Unbiased estimates of the total number of neocortical neurons, as well as the mean neuronal nuclei and cell body volumes were obtained from systematically sampled 3.5-μm sections. The total number of neurons in the 2,5-HD group was significantly smaller than the control group ( p