Molecular biological marker BCL-2: testis analysis in prenatal injection of estrogen to white laboratory mice

Abstract

Immunohistochemical study is one of the modern methods of disease diagnostics used in practical veterinary practice, as well as in scientific developments in differential diagnostics of animal diseases of tumour and non-tumour nature. Prenatal influence of estrogens results in reproductive system disorders in an adult organism which is accompanied by parallel growth of steroid dependent cancers of the offspring: testicles and ovaries. The aim of the study was to perform immunohistochemical analysis of Bcl-2 marker during prenatal exposure to different doses of the synthetic estrogen analogue Sinestrol in the testes of the offspring of white non-pedigreed laboratory mice. After fertilization, the pregnant females were divided into 3 groups, one intact and two experimental groups. The intact group was unaffected (n = 10). The first experimental group, C-25 (n = 13), was injected with the estrogen drug Sinestrol in the form of a 2 % oil solution at a dose of 25 g/kg. The second experimental group (n = 13) was given the estrogen preparation Sinestrol in the form of 2 % oil solution in a dose of 40 mkg/kg. When the offspring reached sexual maturity, they were removed from the experiment. Immunohistochemical analysis was carried out on sections from paraffin blocks of testes of progeny intended for standard morphological study, the marker of apoptosis inhibitor Bcl-2 was determined on indices of cellular elements of male glands of progeny: spermatogonia, spermatocytes, sperm-tides, spermatozoa and Leydig cells. Expression of Bcl-2 marker upon exposure to the synthetic drug Sinestrol at doses of 25 and 40 g/kg showed that the number of positively stained cells in spermatogonia increased by 8.6 and 9.4 % respectively compared to the intact group. When the intact group was compared with experimental groups C-25 and C-40, the expression of Bcl-2 marker in spermatocyte cells and spermatozoa showed no difference, a slight increase in positively stained cells in spermatids was observed. Bcl-2 marker expression rate in experimental groups C 25 and C-40 decreased in Leydig cells by 56.0 (P 0.05) and 60.0 % (P 0.05), respectively. Administration of the synthetic estrogen analogue Sinestrol during fetal gland initiation resulted in impaired morphology in the testes in adulthood. The expression index of Bcl-2 marker in experimental groups C-25 and C-40 decreased in Leydig cells, resulting in apoptotic cell death, which is responsible for production of male sex hormone testosterone. The results can be used to select optimal doses of the synthetic estrogen analogue Sinestrol in the prenatal period.