OBJECTIVE: To elucidate reinitiation factors in human spermatozoa preserved in the electrolyte-free solution at 4 degrees C. SETTING: Andrology laboratory of our hospital. PATIENTS: Semen samples were obtained from patients attending our infertility clinic. INTERVENTIONS: Ejaculated sperm were centrifuged and washed using the electrolyte-free Percoll gradient and then were preserved for 1 week at 4 degrees C. MAIN OUTCOME MEASURES: The motility of preserved sperm was incubated and analyzed after the addition of electrolyte solutions. RESULTS: The motility rate was 9.6% when the preserved sperm were incubated directly. The motility increased to 35.1% after alkalization (pH 7.8) and further increased to 40.7% when 0.1 mM KCl was added. The motility decreased to 1.4% in a weak acidic solution (pH 6.8), however, the addition of a > or = 10 mM concentration of NaCl or > or = 0.1 mM concentration of KCl increased in motility. The motility rate in 40 mM NaCl and 40 mM KCl (pH 6.8) was 19.8% and 31.5%, respectively. The restoration of motility by NaCl was inhibited by 1 mM amiloride. The motility also rose to 54.1% and 32.3% in 0.04% NH3 and 80 mM NH4Cl solution, respectively. CONCLUSIONS: The reinitiation of preserved spermatozoa was induced by potassium ion and extracellular alkalization.
OBJECTIVE: To elucidate reinitiation factors in human spermatozoa preserved in the electrolyte-free solution at 4 degrees C. SETTING: Andrology laboratory of our hospital. PATIENTS: Semen samples were obtained from patients attending our infertility clinic. INTERVENTIONS: Ejaculated sperm were centrifuged and washed using the electrolyte-free Percoll gradient and then were preserved for 1 week at 4 degrees C. MAIN OUTCOME MEASURES: The motility of preserved sperm was incubated and analyzed after the addition of electrolyte solutions. RESULTS: The motility rate was 9.6% when the preserved sperm were incubated directly. The motility increased to 35.1% after alkalization (pH 7.8) and further increased to 40.7% when 0.1 mM KCl was added. The motility decreased to 1.4% in a weak acidic solution (pH 6.8), however, the addition of a > or = 10 mM concentration of NaCl or > or = 0.1 mM concentration of KCl increased in motility. The motility rate in 40 mM NaCl and 40 mM KCl (pH 6.8) was 19.8% and 31.5%, respectively. The restoration of motility by NaCl was inhibited by 1 mM amiloride. The motility also rose to 54.1% and 32.3% in 0.04% NH3 and 80 mM NH4Cl solution, respectively. CONCLUSIONS: The reinitiation of preserved spermatozoa was induced by potassium ion and extracellular alkalization.