Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Via Delpino 1, 80137, Naples, Italy.
Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy; Institute of Biostructures and Bioimages, National Research Council, Via De Amicis 95, 80131, Naples, Italy.
Anim Reprod Sci. 2021 May;228:106735. doi: 10.1016/j.anireprosci.2021.106735. Epub 2021 Mar 11.
Aquaporins (AQPs) are integral transmembrane proteins facilitating transport of water and small solutes, such as glycerol and urea, between cells. In male reproductive tracts, AQPs maintain a milieu conducive for sperm formation, maturation, and storage. The aim of this study was to clarify effects of testicular and epidydimal function on male fertility by investigating localisation and abundances of AQP3 and AQP5 in testes and epididymal segments from dogs with and without unilateral cryptorchidism. Immunohistochemistry results indicated AQP3 and AQP5 have different distribution patterns in reproductive tissues of dogs with and without unilateral cryptorchidism. The AQP3, an aquaglyceroprotein, is present in different germ and Sertoli cells in testis of dogs without cryptorchidism. The AQP5 protein was not detected in germ cells but was present in Sertoli and Leydig cells and in endothelia of blood vessels. In cryptorchid dogs, AQP3 was detected in early-developing germ and Sertoli cells, and AQP5 had a distribution pattern similar to testes of dogs without cryptorchidism. In the epididymis, AQP3 and AQP5 were localised in epithelial cells of dogs with and without cryptorchidism in a cell-specific manner. The AQP3 and AQP5 protein was in larger abundance in the gonads from dogs with and without cryptorchidism. In contrast, AQP3 and AQP5 abundance increased in each segment of the cryptorchid epididymis, likely as a compensatory mechanism associated with the pathologic condition. These results indicate involvement of AQP3 and AQP5 in spermatogenesis and sperm maturation. Results from the present study indicate dogs are a useful for comparative reproductive biology studies.
水通道蛋白（AQP）是一种完整的跨膜蛋白，促进水和甘油、尿素等小分子在细胞间的运输。在男性生殖道中，AQP 维持着有利于精子形成、成熟和储存的环境。本研究旨在通过研究有无单侧隐睾犬睾丸和附睾各段中 AQP3 和 AQP5 的定位和丰度，阐明睾丸和附睾功能对雄性生育力的影响。免疫组织化学结果表明，有无单侧隐睾犬生殖组织中 AQP3 和 AQP5 分布模式不同。AQP3 是一种水甘油蛋白，存在于无隐睾犬睾丸不同的精原细胞和支持细胞中。AQP5 蛋白未在精原细胞中检测到，但存在于支持细胞和间质细胞以及血管内皮中。在隐睾犬中，AQP3 存在于早期发育的精原细胞和支持细胞中，AQP5 的分布模式与无隐睾犬的睾丸相似。在附睾中，AQP3 和 AQP5 以细胞特异性的方式定位于有无隐睾犬的上皮细胞中。AQP3 和 AQP5 蛋白在有无隐睾犬的性腺中丰度较大。相比之下，AQP3 和 AQP5 的丰度在隐睾附睾的各段中增加，可能是与病理状况相关的代偿机制。这些结果表明 AQP3 和 AQP5 参与精子发生和精子成熟。本研究结果表明，犬是一种用于比较生殖生物学研究的有用动物。
