Dendritic and microglial cells in pups of alcohol-treated female rats

Alcohol ingestion by female rats during pregnancy and/or lactation leads to developmental anomalies of different organ systems, retardation and immune system impairment in their offspring. In humans, these disorders are termed foetal alcohol syndrome (FAS), or foetal alcohol effect (FAE) if abnormalities are of lesser degree. The study materials consisted of brain, liver and spleen samples collected ten days post partum from neonatal rats born to dams treated with 12% alcohol at a dose of 6 g/kg body mass during pregnancy or during pregnancy and/or lactation. Microglial and dendritic cells were assessed by light (histochemical and immunohistochemical methods) and electron microscopes. Histochemically, the presence of microglia (ramified, amoeboid and rod) and dendritic cells in the studied organs was detected, but only some of them demonstrated the expression of major histocompatibility complex, class I and II (MHC I, II) on their surfaces. Ultrastructural observations revealed immature morphology of part microglial cells, whereas their euchromatin nuclei maybe showed rather high transcription activity. The preliminary study of dendritic cells at ultrastructural level does not indicate pronounced changes. Abnormalities were mostly pronounced in pups born to alcohol-treated dams during pregnancy and during pregnancy and lactation. These observations suggest that microglia and dendritic cells may be regarded as early markers of alcohol-induced impairments. The reduced immune efficiency in animal FAS/FAE models may be due to both immaturity of these cells and low expression of MHC I and II molecules, which renders it difficult for microglial and dendritic cells to present foreign antigens to helper lymphocytes T, which delays the cascade of immune response.