[The characteristics of the structural development of the thymus and spleen in the progeny of white rats exposed to pyrogenal action during pregnancy].

Thymus and spleen structural changes of progeny of experimental animals after single exposure to 100-150 mg/l kg of bacterial pyrogenal lipopolysaccharide on 11th, 14 and 18th days of pregnancy were studied in the experiment performed on 60 female outbred albino rats and 205 rats--pups aged 20- and 45 days. Relative thymus and spleen masses were defined, their morphofunctional state was assessed morphometrically. To reveal the pecularities of the immune system reaction to foreign antigens in progeny, one part of control and experimental rats were subjected to immunization with ram erythrocytes (T-dependent antigen) and another one--with pyrogenal (T-independent antigen). Prenatal pyrogenal effect retarded thymus and spleen formation. Normalization of their structure and compensation of the effect were incomplete and occurred by 45th day of postnatal development. Most expressed changes were observed in the progeny of the rats treated with pyrogenal on 14th day of pregnancy: sharp decrease of the population density of lymphoid cells occurred in the thymus while lymphoid nodules disappeared in the spleen in response to immune challenge.