Henning H, Masal C, Herr A, Wolf K, Urhausen C, Beineke A, Beyerbach M, Kramer S, Günzel-Apel A-R
Unit for Reproductive Medicine of Clinics, University of Veterinary Medicine Hannover, Hannover, Germany; Clinic for Pigs and Small Ruminants, University of Veterinary Medicine Hannover, Hannover, Germany.
Reprod Domest Anim. 2014 Feb;49(1):145-57. doi: 10.1111/rda.12244. Epub 2013 Nov 6.
The objective was to assess the effect of a short-term scrotal hyperthermia in dogs on quantitative and qualitative ejaculate parameters, testicular blood flow and testicular and epididymal histology. After a control period, the scrotum of seven normospermic adult beagle dogs was insulated with a self-made suspensory for 48 h. Nine weeks later, two animals were castrated, while in five animals, scrotal hyperthermia was repeated. Dogs were castrated either 10 or 40 days thereafter. In each phase of scrotal insulation, average scrotal surface temperature increased by 3.0°C. Semen was collected twice weekly throughout the experiment. Total sperm count did not change after the first hyperthermia, but it slightly decreased after the second (p < 0.05). Profiles of sperm morphology and velocity parameters (CASA) rather indicated subtle physiological variations in sperm quality than effects of a local heat stress. Chromatin stability of ejaculated spermatozoa as indicated by SCSA remained constant throughout the experiment. Perfusion characteristics of the gonads, that is, systolic peak velocity, pulsatility and resistance index at the marginal location of the testicular artery, did not change due to hyperthermia (p > 0.05). Histological examination of excised testes and epididymides for apoptotic (TUNEL and activated caspase-3) and proliferating cells (Ki-67 antigen) indicated only marginal effects of scrotal insulation on tissue morphology. In conclusion, a mild short-term scrotal hyperthermia in dogs does not cause substantial changes in sperm quantity and quality. In contrast to other species, canine testes and epididymides may have a higher competence to compensate such thermal stress.
目的是评估犬短期阴囊高温对射精参数的定量和定性、睾丸血流以及睾丸和附睾组织学的影响。在对照期后，用自制吊带对7只精子正常的成年比格犬的阴囊进行隔热处理48小时。9周后，对2只动物实施去势，而另外5只动物再次进行阴囊高温处理。此后10天或40天对犬实施去势。在阴囊隔热的每个阶段，阴囊表面平均温度升高3.0°C。在整个实验过程中每周收集两次精液。第一次高温处理后精子总数没有变化，但第二次后略有下降（p<0.05）。精子形态和速度参数（计算机辅助精子分析）的概况表明精子质量存在细微的生理变化，而非局部热应激的影响。精子染色质结构分析（SCSA）所示的射出精子的染色质稳定性在整个实验过程中保持不变。由于高温处理，性腺的灌注特征，即睾丸动脉边缘位置的收缩期峰值速度、搏动性和阻力指数没有变化（p>0.05）。对切除的睾丸和附睾进行凋亡（TUNEL和活化的半胱天冬酶-3）和增殖细胞（Ki-67抗原）的组织学检查表明，阴囊隔热对组织形态的影响很小。总之，犬轻度短期阴囊高温不会导致精子数量和质量发生实质性变化。与其他物种相比，犬的睾丸和附睾可能具有更高的能力来补偿这种热应激。
