A new model for investigating in real-time the existence of Chemotaxis in human spermatozoa

Abstract

To suggest a new approach to the research of chemotaxis between various media and human spermatozoa to solve the riddle of its existence. Laboratory experiments in which chemotaxis between human spermatozoa and follicular fluid (FF) as well as N-formyl was investigated. Male physiology laboratory and in vitro fertilization program unit. Follicular fluid was collected from 15 patients and used either fresh or after storage at -5 degrees C for less than 2 weeks. High-quality semen specimens were obtained from normal donors and underwent one-step washing with Ham's F-10 solution (Biological Industries, Kibbutz Beth Haemek, Israel). Assays were performed in real time by direct microscopical observation and quantitative determination of the disturbance in random movements of human spermatozoa caused by the tested media. Spermatozoa and tested media, including FF and N-formyl-Met-Leu-Phe were placed in a sealed minichamber and photographed with the aid of the multiple exposure photography technique. By analyzing photographed tracks of more than 80,000 moving spermatozoa, a physiologically insignificant deviation from randomness, corresponding to a 95% confidence interval of -0.57 +/- 0.46%, was found when spermatozoa swam along the concentration gradient of the tested media. The average velocity of spermatozoa swimming toward the test media was slightly lower (less than 5%) than that for spermatozoa swimming away, indicating, if anything, negative chemoattraction. Despite the high sensitivity of the model, neither natural FF nor synthetic N-formyl exerted any chemotaxis on human sperm. The advantages and potential use of this model for investigating chemotaxis by other biological and synthetic media are discussed.