Centre for Feline Nutrition, School of Agriculture and Environment, College of Science, Massey University, Private Bag 11-222, Palmerston North, 4442, New Zealand.
School of Veterinary Science, College of Science, Massey University, Private Bag 11-222, Palmerston North, 4442, New Zealand.
Theriogenology. 2022 Sep 1;189:20-30. doi: 10.1016/j.theriogenology.2022.05.026. Epub 2022 May 31.
Elevated glucocorticoid (GC) concentrations associated with captivity-related stress have been linked to impaired testicular function and low sperm quality in felids, but direct physiological evidence is lacking. This study assessed the effects of exogenous GC treatment on felid testicular function using the domestic cat (Felis catus) as a model species. Sixteen intact male cats aged 2.4 ± 0.8 years (mean ± SEM) were divided randomly into treatment (n = 8) and control (n = 8) groups. Treatment cats were given 1 mg kg oral prednisolone daily for 50 days. Blood samples were taken on Days 0 (first prednisolone treatment), 2, 4, 7, 10, 20, 30, 40, 50 (prior to neutering) and 60 of the trial. All cats were orchiectomised on day 50, epididymal sperm assessed, and the testes fixed for histological assessment. Testosterone concentrations did not differ between the two groups. While sperm motility was similar between the treatment and control groups, cats given prednisolone had a higher proportion of morphologically abnormal sperm in both the caput (72.5% vs. 59.6%, P < 0.001) and cauda (56.7% vs. 35.8%, P < 0.001) epididymis. Testicular histomorphometric data and total number of germ cells per seminiferous tubule cross section did not differ between groups, nor did the relative abundance of spermatogonia, spermatocytes, and spermatids. Cats given prednisolone had fewer Sertoli cells per tubule cross-section than those in the control group (17.1 ± 0.9 vs. 19.7 ± 0.8, P = 0.04), which was likely related to higher rates of Sertoli cell apoptosis in treatment versus control cats (0.25 ± 0.02 vs. 0.10 ± 0.02 apoptotic Sertoli cells per tubule, respectively; P < 0.001). Sertoli cell load (number of germ cells per Sertoli cell) was also higher in the treatment group than in the control group (11.5 ± 0.8 vs. 9.4 ± 1.2 germ cells per Sertoli cell, respectively; P < 0.001), and was positively correlated with the percentage of morphologically abnormal sperm in the epididymis (r = 0.78, P < 0.001). Prednisolone treatment resulted in an increase in the proportion of abnormal sperm in the epididymis, which may be explained by an increased nurturing demand on a reduced Sertoli cell population. These findings provide novel evidence to support the hypothesis that elevated GC concentrations, such as those resulting from captivity-related stress, have the potential to impair testicular function and sperm quality in felids.
与圈养相关的应激相关的糖皮质激素 (GC) 浓度升高与猫科动物的睾丸功能受损和精子质量下降有关，但缺乏直接的生理证据。本研究使用家猫（Felis catus）作为模型物种，评估了外源性 GC 处理对猫科动物睾丸功能的影响。16 只年龄为 2.4±0.8 岁（平均值±SEM）的完整雄性猫随机分为治疗（n=8）和对照组（n=8）。治疗组猫每天口服 1mg/kg 泼尼松龙，持续 50 天。在试验的第 0 天（第一次泼尼松龙治疗）、第 2、4、7、10、20、30、40、50 天（绝育前）和第 60 天采集血液样本。所有猫在第 50 天进行睾丸切除术，评估附睾精子，并固定睾丸进行组织学评估。两组之间的睾酮浓度没有差异。虽然治疗组和对照组的精子活力相似，但给予泼尼松龙的猫的精子形态异常比例更高，在头（72.5%比 59.6%，P<0.001）和尾（56.7%比 35.8%，P<0.001）附睾中均如此。睾丸组织形态计量学数据和每个生精小管横截面积的总生殖细胞数在两组之间没有差异，精原细胞、精母细胞和精子细胞的相对丰度也没有差异。与对照组相比，给予泼尼松龙的猫每个管横截面积的支持细胞更少（17.1±0.9 比 19.7±0.8，P=0.04），这可能与治疗组与对照组相比支持细胞凋亡率更高有关（0.25±0.02 比 0.10±0.02 个管的凋亡支持细胞，分别；P<0.001）。与对照组相比，治疗组的支持细胞负荷（每个支持细胞的生殖细胞数）也更高（11.5±0.8 比 9.4±1.2 个生殖细胞/支持细胞，分别；P<0.001），并且与附睾中形态异常精子的百分比呈正相关（r=0.78，P<0.001）。泼尼松龙治疗导致附睾中异常精子比例增加，这可能是由于支持细胞数量减少，对精子的培育需求增加所致。这些发现提供了新的证据，支持这样的假设，即升高的 GC 浓度，如与圈养相关的应激引起的浓度，有可能损害猫科动物的睾丸功能和精子质量。
