[Structural characteristics of the thymus in the antenatal and early postnatal periods of ontogeny in tetracycline exposure].

Structural peculiarities of the thymus have been studied in Wistar rats during antenatal and early postnatal periods of ontogenesis under the effect of tetracycline hydrochlorid administered in therapeutic doses to the system mother--fetus during preimplantation period of the fetus development (the 1st - 6th days). Histological, histochemical, electron microscopical and morphometrical methods have been used. Ultrastructural changes of epithelioreticulocytes and thymocytes, a delayed appearance of the subcapsular zone, a delayed division of the thymus lobules into the cortex and medullar substance, a decreasing content of all cellular forms of the lymphoid line during the intrauterine development have been revealed, as well as a decreased amount of small lymphocytes at all stages of the antenatal and early postnatal periods of ontogenesis. The data obtained are considered as a result of a toxic effect of the antibiotic.