EFFECT OF EXTERNAL IRRADIATION ON EMBRYOGENESIS OF THE ADRENAL GLANDS OF THE WHITE RAT

Abstract

Purpose - to establish the regularities of the development of the adrenal glands of embryos of the white rat in normal conditions and under the influence of external irradiation. Materials and methods. The development of the adrenal glands of the embryos of the white rat was researched from 12 to 22 days of embryogenesis. We used specimens of white rat embryos from 8 mm CRL to 40 mm CRL from the embryological collection of the Department of Normal Anatomy of the Belarusian State Medical University in the amount of 29 series of embryo sections. 14 series belong to normal embryos, 9 series were irradiated on days 12-13 and 6 series were irradiated on days 15-16. Normally, the anlage of the adrenal glands of the white rat appears on the 12th day of embryogenesis (8 mm CRL). Sinusoids are formed on the 13th day (9 mm CRL). On the 14th day (10 mm CRL), sympathoblasts appear around the organ, inside the gland they were found on the 15th day (12 mm CRL). At the same time, a thin walled capsule is formed, the cortex is divided into definitive and fetal zones. In an embryo of 17 days of development (18 mm CRL), medullar balls in the center of the adrenal gland are observable. On the 21st day of embryogenesis (36 mm CRL), the adrenal gland is practically formed, has developed structural elements. When the radiation is exposed on the 12-13th day, there is a significant inhibition of the growth and development of the organ. Sinusoids are characterized by a narrow lumen, especially at the periphery. The adrenal gland is completely surrounded by a capsule only on the 16th day, there we can see isolated sympathoblasts. Medullar balls are formed on the 18th day. There are all structural elements in the gland by 21-22 days. However, in comparison with the norm, the gland is underdeveloped. In the adrenal gland irradiated on the 15-16th day, structural changes are less pronounced. By the 22nd day, the organ is comparable in its rate of development with the non irradiated one. In the development of the adrenal glands of the embryo of the white rat, the following stages can be distinguished: 1) the stage of organ initiation and the beginning of the invasion of sympathoblasts; 2) the formation of medullar balls; 3) the final differentiation of cells and the formation of the basic structures of the adrenal gland. External irradiation at the time of organ laying (12-13 days) causes a delay in the onset of stages 2 and 3, which leads to the underdevelopment of the organ by the time of birth. A later exposure to radiation (15-16 days) leads to less pronounced morphological changes.