Histological changes of the testis and epididymis in adult rats as a result of Leydig cell destruction after ethane dimethane sulfonate treatment： a morphometric study

Aim： To quantitatively study the histological changes of the testis and epididymis as a result of a drastic reduction of testosterone secretion. Methods： Fourteen adult Sprague-Dawley rats were injected intraperitoneally with ethane dimethane sulfonate （EDS, 75 mg/kg） and the same number of animals were injected with normal saline as a control. At days 7 and 12 （after treatment）, respectively, half of the animals from each group were killed. The testes and epididymides were removed and tissue blocks embedded in methacrylate resin. The cell number per testis was estimated using the stereological optical disector and some other parameters were obtained using other morphometric methods. Results： The EDS treatment resulted in an almost complete elimination of Leydig cells but had no effect on the numbers of Sertoli cells per testis. At day 7 after EDS treatment, many elongated spermatids were retained in the seminiferous epithelium and many round spermatids could be seen in the epididymal ducts. At day 12, a looser arrangement of spermatids and spermatocytes became evident, with apparent narrow empty spaces being formed between germ cells in an approximately radial direction towards the tubule lumen; the numbers （per testis） of non-type B spermatogonia and spermatocytes were similar to controls, whereas that of type B spermatogonia increased by 59%, and that of early round, elongating and late elongated spermatids decreased by 37%, 72% and 52%, respectively. Conclusion： The primary spermatogenic lesions following EDS administration were （i） spermiation failure and （ii） detachment of spermatids and spermatocytes associated with impairment in spermiogenesis and meiosis.

Differential expression and regulation of integral membrane protein 2b in rat male reproductive tissues

Aim： To examine the expression and regulation of integral membrane protein 2b （Itm2b） in rat male reproductive tissues during sexual maturation and under different treatments by in situ hybridization. Methods： Testis, epididymis, and vas deferens were collected on days 1-70 to examine Itm2b expression during sexual maturation. To further examine the regulation of Itm2b, adult rats underwent surgical castration and cryptorchidism. Ethylene dimethane sulfonate and busulfan treatments were carried out to test the regulation of Itm2b after destruction of Leydig cells and germ cells. Results： In testis, Itm2b expression was moderately detected in the adluminal area of seminiferous cords on days 1-10, and detected at a low level in the spermatogonia on days 20 and 30. The Itm2b level was markedly increased in Leydig cells from day 20 to day 70. In epididymis and vas deferens, Itm2b was detected from neonate to adults, and the signal gradually increased in accordance with sexual maturation. Itm2b expression was significantly downregulated in epididymis and vas deferens of castrated rats, and strongly stimulated when castrated rats were treated with testosterone. Cryptorchidism led to a significant decline of Itm2b expression in testis and caput epididymis. Itm2b expression in epididymis and vas deferens was significantly decreased after the Leydig ceils were destroyed by ethylene dimethane sulfonate. Busulfan treatment produced no obvious change in Itm2b expression in epididymis or vas deferens. Conelusion： Our data suggested that Itm2b expression is upregulated by testosterone and might play a role in rat male reproduction.

Histological changes of the testis and epididymis in adult rats as a result of Leydig cell destruction after ethane dimethane sulfonate treatment:a morphometric study

Aim:To quantitatively study the histological changes of the testis and epididymis as a result of a drastic reduction of testosterone secretion.Methods:Fourteen adult Sprague-Dawley rats were injected intraperitoneally with ethane dimethane sulfonate(EDS,75 mg/kg)and the same number of animals were injected with normal saline as a control. At days 7 and 12(after treatment),respectively,half of the animals from each group were killed.The testes and epididymides were removed and tissue blocks embedded in methacrylate resin.The cell number per testis was esti- mated using the stereological optical disector and some other parameters were obtained using other morphometric methods.Results:The EDS treatment resulted in an almost complete elimination of Leydig cells but had no effect on the numbers of Sertoli cells per testis.At day 7 after EDS treatment,many elongated spermatids were retained in the seminiferous epithelium and many round spermatids could be seen in the epididymal ducts.At day 12,a looser arrangement of spermatids and spermatocytes became evident,with apparent narrow empty spaces being formed between germ cells in an approximately radial direction towards the tubule lumen;the numbers(per testis)of non- type B spermatogonia and spermatocytes were similar to controls,whereas that of type B spermatogonia increased by 59%,and that of early round,elongating and late elongated spermatids decreased by 37%,72% and 52%,respectively. Conclusion:The primary spermatogenic lesions following EDS administration were(i)spermiation failure and(ii) detachment of spermatids and spermatocytes associated with impairment in spermiogenesis and meiosis.