Prieto-Martínez Noelia, Morató Roser, Muiño Rodrigo, Hidalgo Carlos O, Rodríguez-Gil Joan E, Bonet Sergi, Yeste Marc
Department of Biology, Institute of Food and Agricultural Technology, University of Girona, C/ Maria Aurèlia Campany 65, Campus Montilivi, E-17071 Girona, Spain.
Department of Animal Pathology, University of Santiago de Compostela, Avda. Carballo Calero s/n, E-27002 Lugo, Spain.
Reprod Fertil Dev. 2017 Jun;29(6):1249-1259. doi: 10.1071/RD16077.
The present study aimed to determine the localisation of aquaglyceroporins 3 (AQP3) and 7 (AQP7) in bull spermatozoa and their relationship with the sperm cell's resilience to withstand cryopreservation (i.e. cryotolerance). A total of 18 bull ejaculates were cryopreserved and their sperm quality analysed before and after freeze-thawing. The presence and localisation of AQP3 and AQP7 was determined through immunoblotting and immunocytochemistry. AQP3 was found in the mid-piece and AQP7 in the mid-piece and post-acrosomal region of bull spermatozoa. Immunoblotting showed specific signal bands at 30 and 60kDa for AQP3 and at 25kDa for AQP7. Neither the relative abundance of AQP3 and AQP7 nor their localisation patterns was altered by cryopreservation but individual differences between bull ejaculates were found in immunoblots. In order to determine whether these individual differences were related to sperm cryotolerance, bull ejaculates were classified as having good (GFE) or poor freezability (PFE) on the basis of their sperm quality after thawing. While the relative abundance of AQP3 before cryopreservation did not differ between ejaculates with GFE and PFE, the abundance of AQP7 was higher in GFE than in PFE ejaculates. This finding was further confirmed through principal component and linear regression analyses. In conclusion, the relative abundance of AQP7 in fresh semen may be used as a marker to predict bull sperm cryotolerance.
本研究旨在确定水甘油通道蛋白3（AQP3）和7（AQP7）在公牛精子中的定位及其与精子细胞耐受冷冻保存能力（即冷冻耐受性）的关系。总共18份公牛精液被冷冻保存，并在冻融前后分析其精子质量。通过免疫印迹和免疫细胞化学确定AQP3和AQP7的存在和定位。在公牛精子的中段发现了AQP3，在中段和顶体后区域发现了AQP7。免疫印迹显示AQP3在30和60kDa处有特异性信号带，AQP7在25kDa处有特异性信号带。冷冻保存既未改变AQP3和AQP7的相对丰度，也未改变其定位模式，但在免疫印迹中发现公牛精液之间存在个体差异。为了确定这些个体差异是否与精子冷冻耐受性有关，根据解冻后的精子质量将公牛精液分为冷冻性能良好（GFE）或冷冻性能差（PFE）两类。虽然冷冻保存前AQP3的相对丰度在GFE和PFE精液之间没有差异，但GFE精液中AQP7的丰度高于PFE精液。这一发现通过主成分分析和线性回归分析得到了进一步证实。总之，新鲜精液中AQP7的相对丰度可作为预测公牛精子冷冻耐受性的标志物。
