Sperm Na~+, K~+-ATPase and Ca~(2+)-ATPase activity: A preliminary study of comparison of swim up and density gradient centrifugation methods for sperm preparation

摘要

As one of the treatment for infertility, the success rate of Intrauterine Insemination (IUI) is still relatively low. Several sperm preparation methods, swim-up (SU) and the density-gradient centrifugation (DGC) are frequently used to select for better sperm quality which also contribute to IUI failure. Sperm selection methods mainly separate the motile from the immotile sperm, eliminating the seminal plasma. The sperm motility involves the structure and function of sperm membrane in maintaining the balance of ion transport system which is regulated by the Na~+, K~+-ATPase, and Ca~(2+)-ATPase enzymes. This study aims to re-evaluate the efficiency of these methods in selecting for sperm before being used for IUI and based the evaluation on sperm Na~+, K~+-ATPase and Ca~(2+)-ATPase activities. Fourteen infertile men from couples who underwent IUI were involved in this study. The SU and DGC methods were used for the sperm preparation. Semen analysis was performed based on the reference value of World Health Organization (WHO) 2010. After isolating the membrane fraction of sperms, the Na~+, K~+-ATPase activity was defined as the difference in the released inorganic phosphate (Pi) with and without the existence of 10 mM ouabain in the reaction, while the Ca~(2+)-ATPase was determined as the difference in Pi contents with and without the existence of 55μm CaCl~2. The prepared sperm demonstrated a higher percentage of motile sperm compared to sperm from the whole semen. Additionally, the percentage of motile sperm of post-DGC showed higher result than the sperm from post-SU. The velocity of sperm showed similar pattern with the percentage of motile sperm, in which the velocity of prepared sperm was higher than the sperm from whole semen. Furthermore, the sperm velocity of post-DGC was higher compared to the sperm from post-SU. The Na~+, K~+-ATPase activity of prepared sperm was higher compared to whole semen, whereas Na~+, K~+-ATPase activity in the post DGC was higher than post SU. The Ca~(2+)-ATPase activity of prepared sperm was higher compared to whole semen, whereas Ca~(2+)-ATPase activity in the post DGC was higher than post SU. The SU and the DGC methods were able to perform sperm selection by showing a high result of Na~+, K~+-ATPase and Ca2+-ATPase activities, moreover DGC method selected the sperm with high activities of both the Na+, K+-ATPase and Ca~(2+)-ATPase better compared to SU method.