A single neonatal administration of soybean oil and/or tamoxifen affects permanently the testis histomorphology in adult rats.

Veterinaria Mexico OA ISSN: 2448-6760 Cite this as: Gonzalez Gonzalez A, Gonzalez Padilla E, Fierro Fierro F, Juarez Mosqueda M de L, Perez Rivero JJ, Vergara Onofre M. A single neonatal administration of soybean oil and/or tamoxifen affects permanently the testis histomorphology in adult rats. Veterinaria Mexico OA. 2016;3(2). doi: 10.21753/vmoa.3.2.364 The aim of this study was to determine the effect of tamoxifen (Tx) and its vehicle, soybean oil (SO), during the critical period of hypothalamic sexual differentiation in newborn male rats, regarding gonadal histomorphology during adulthood. The animals were randomly divided into 3 groups (n = 5 each). An hour after birth, one group was treated subcutaneously with 200 μg of Tx, using commercial SO (20 uL) as a vehicle; another group was treated with only 20 μL of SO; the control group received no treatment. All rats were weighed and sacrificed by cervical dislocation on day 90 post-treatment. Testicles were removed, weighed and processed for histological evaluation. The single administration of Tx and/or SO during the critical period of sexual differentiation of the hypothalamus permanently altered testicular histomorphology, spermatogenesis, and body weight in adulthood. Alterations included vacuolization and reduction in the number of spermatogonia and Sertoli cells. The administration of Tx reduced the testicular weight, the diameter and area of the seminiferous tubules, and the height of the germinal epithelium, and increased the intertubular space. Soybean oil by itself reduced the number of spermatocytes and spermatids more than Tx did. There was no effect on the number of Leydig cells. The possibility that soybean oil can act as an endocrine disruptor deserves greater attention and opens the possibility for the development of new methods of pest control. Figure 1. Representative hematoxylin-eosin-stained histological sections of testicles collected from the control group (A y B), rats treated with SO (C y D) and rats treated with Tx (E y F). A, C and E, 200X. B, D and F, 400X. T: Tubule. LC: Leydig cells. Histological changes induced by Tx and/or SO treatments can be observed. Black arrows point to the largest intertubular space. White arrows in E and F indicate the ungrouping of the LC. Asterisks indicate the vacuoles in the seminiferous tubules.