The effects of maternal ethanol consumption on the distribution of leukocyte subsets in the lactating mammary gland of rats.

Significant immunological protection is provided to the newborn by the transfer of maternal leukocytes during nursing. The objective of this study was to determine if ethanol ingestion altered the distribution of T, B and accessory cells in the mammary glands of normal rats or in rats infected with Trichinella spiralis (T. spiralis). In addition, female rats were fed either Lieber/DeCarli regular (18% protein) or higher protein (25% protein) ethanol-containing liquid diets for pregnant or lactating rats or were pair-fed the corresponding isocaloric control diets to assess changes in cellular distribution due to dietary content. In the first experiment (short-term ethanol), animals were placed on either 18 or 25% protein diet (ethanol or pair-fed) on day 1 of pregnancy. In the second experiment (long-term ethanol), animals were placed on 18% protein diet (ethanol or pair-fed) for 30 days prior to mating, mated and then placed on either 25% protein diet (18%/25% animals) or kept on 18% protein diet (18%/18% animals) through pregnancy and lactation. In the third experiment (long-term ethanol, immunized), animals were fed 18%/25% protein diet (ethanol or pair-fed) as in experiment 2 and were infected intragastrically with 1000 T. spiralis larva on day 15 of pregnancy. All animals were sacrificed on day 2 of lactation, the mammary gland removed and weighed. Frozen sections of mammary gland from each animal were incubated with monoclonal antibodies directed against antigens associated with rat T cells (W3/13), suppressor/cytotoxic (OX8) or helper (W3/25) T cell subsets, macrophages (ED2) or rat IgA (B cells) and processed for peroxidase anti-peroxidase (PAP) immunocytochemistry. The total number of antigen positive leukocytes/high powered microscope field (hpf), intraepithelial leukocytes/hpf and alveolar connective tissue leukocytes/hpf was determined for each stain by counting 100 hpf and the data were compared by statistical analysis. Significant differences in mammary gland weight between ethanol-treated and pair-fed animals were observed in the long-term 18%/18% protein diet experiment in which animals fed ethanol had significantly lower mammary gland weights. Ethanol-treated short-term animals maintained on the 18% protein diet through pregnancy, showed decreased numbers of IgA+ B cells and W3/13+ T cells/hpf in the alveolar connective tissue compartment and this decrease was reflected in total cells/hpf. Long-term 18%/18% protein diet, ethanol-fed animal showed increases in total IgA+ B cells and W3/13+ T cells/hpf as compared with pair-fed controls.(ABSTRACT TRUNCATED AT 400 WORDS)