Forebrain damage in chick embryos exposed to carbon monoxide

The consequences of CO-induced hypoxia to the forebrain of seven-day-old chick embryos were investigated. Exposure of embryos to CO for three hours caused hemorrhages in developing forebrain areas. Carboxyhemoglobin levels reached about 50% in the embryos. Two weeks later, about one day prior to hatching, morphology of large neurons in the paleostriatum primitivum was evaluated. In Golgi-stained sections examined under the light microscope, the CO-exposed chicks were found to have reduced branching of the dendritic tree. In addition, the nuclear size of the paleostriatum primitivum neurons was reduced in the CO-exposed chicks. These findings in chick embryos are comparable to results in previous experiments with fetal rats.