Long-term sequelae of perinatal asphyxia in the aging rat.

Information on the consequences of perinatal asphyxia (PA) on brain morphology and function in the aging rat is missing although several groups have hypothesized that PA may be responsible for neurological and psychiatric deficits in the adult. We therefore decided to study the effects of PA on the central nervous system (CNS) in terms of morphology, immunohistochemistry, neurology and behavior in the aging animal. Hippocampus and cerebellum were evaluated morphologically by histological, immunohistochemical and magnetic resonance imaging and cerebellum also by stereological tests. Neurological function was tested by an observational test battery and rota rod test. Cognitive functions were examined by multiple-T-maze and the Morris water maze (MWM). Increased serotonin transporter (SERT) immunoreactivity in the CA2 region of the hippocampus and a significant difference in the escape latency, when the platform of the MWM was moved to a new location, were observed in asphyxiated rats. We showed that deteriorated cognitive functions accompanied by aberrant expression of hippocampal SERT and impaired relearning are long-term sequelae of perinatal asphyxia, a finding that may form the basis for understanding CNS pathology in the aging subject, animal or human.

The volume of Purkinje cells decreases in the cerebellum of acrylamide-intoxicated rats, but no cells are lost.

The effects of acrylamide intoxication on the numbers of granule and Purkinje cells and the volume of Purkinje cell perikarya have been evaluated with stereological methods. The analysis was carried out in the cerebella of rats that had received a dose of 33.3 mg/kg acrylamide, twice a week, for 7.5 weeks. The total numbers of cerebellar granule and Purkinje cells were estimated using the optical fractionator and the mean volume of the Purkinje cell perikarya was estimated with the vertical rotator technique. The volumes of the molecular layer, the granular cell layer and the white matter were estimated using the Cavalieri principle. The mean weight of the cerebellum of the intoxicated rats was 7% lower than that of the control rats (2P = 0.001). The numbers of the Purkinje cells and granule cells were the same in both groups, but the mean volume of the perikarya of the Purkinje cells in the intoxicated rats was 10.5% less than that of the control group (2P = 0.004). The volume of the granular cell layer was reduced by 15% (2P = 0.006) but there were no differences in the volumes of the molecular layer and the white matter in the intoxicated and control animals.