Junaidi A, Williamson P E, Trigg T E, Cummins J M, Martin G B
Division of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, WA, Australia.
Reprod Domest Anim. 2009 Oct;44(5):757-63. doi: 10.1111/j.1439-0531.2008.01066.x.
The present study is part of a programme of research designed to evaluate the efficacy of the GnRH superagonist,deslorelin (D-Trp6-Pro9-des-Gly10-LHRH ethylamide), as a contraceptive for male dogs. Adult dogs were assigned to a completely randomized design comprising six groups of four animals. Each dog in the control group received a blank implant (placebo) and each dog in the other five groups received a 6 mg deslorelin implant. One group of deslorelin treated dogs was sacrificed on each of days 16, 26, 41, 101 and 620, and testicular and prostate tissues were collected for study by light and electron microscopy. On days 16 and 26 after implantation, we observed partial disruption of the seminiferous tubules, with early spermatids shed into the lumen. On days 41 and 101 after implantation, 90–100% of the seminiferous tubules were atrophic and aspermatogenic.On day 101 after implantation, 99% of all sections showed atrophy of the epithelium and shrinkage of epithelial height in the ductus epididymides. On days 41 and 101 after implantation, prostate tissue showed complete atrophy of the glandular epithelium (100% of sections) and an apparent increase in the relative proportion of connective tissue. At the electron microscopic level, in dogs treated with deslorelin for 41 and 101 days, the Sertoli cells were smaller and their nucleoli appeared smaller than in the control dogs. The nucleoli of the Leydig cells were atrophied and prostate glandular epithelium showed reduced epithelial height, a trophy of the nucleolus and an absence of secretory granules.Tissues collected during the recovery phase revealed a complete recovery of spermatogenesis. In conclusion, slow release implants containing deslorelin induce a striking a trophy of the testes and prostate gland by 26 days after implantation, explaining the previously reported loss of ejaculate and arrest of sperm output. At histological level,the entire process appears to be completely reversible, in accordance with data on endocrine variables and semen production.
本研究是一项研究计划的一部分，该计划旨在评估促性腺激素释放激素（GnRH）超激动剂地洛瑞林（D-色氨酸6-脯氨酸9-去甘氨酸10-促黄体生成素释放激素乙酰胺）作为雄性犬类避孕药的功效。成年犬被分配到一个完全随机设计中，该设计包括六组，每组四只动物。对照组中的每只犬接受一个空白植入物（安慰剂），其他五组中的每只犬接受一个6毫克的地洛瑞林植入物。在植入后的第16、26、41、101和620天，每组处死一只接受地洛瑞林治疗的犬，并收集睾丸和前列腺组织，用于光镜和电镜研究。植入后第16天和26天，我们观察到生精小管部分破坏，早期精子细胞脱落至管腔。植入后第41天和101天，90%-100%的生精小管萎缩且无精子发生。植入后第101天，所有切片中有99%显示附睾管上皮萎缩和上皮高度缩小。植入后第41天和101天，前列腺组织显示腺上皮完全萎缩（100%的切片），结缔组织相对比例明显增加。在电子显微镜水平上，用地洛瑞林治疗41天和101天的犬，其支持细胞比对照犬小，核仁也较小。间质细胞的核仁萎缩，前列腺腺上皮显示上皮高度降低、核仁萎缩且无分泌颗粒。在恢复阶段收集的组织显示精子发生完全恢复。总之，含地洛瑞林的缓释植入物在植入后26天可引起睾丸和前列腺显著萎缩，这解释了先前报道的射精量减少和精子输出停止。在组织学水平上，根据内分泌变量和精液生成的数据，整个过程似乎是完全可逆的。
