A comparison of heat-induced hyperactivation in patients' sperm after colloid or pentoxifylline wash methods

OBJECTIVE: Our purpose was to compare kinematic parameters of human sperm a fter processing through two different wash methods and 40 degreesC heat tre atment. STUDY DESIGN: Sperm specimens (N = 169 cases) were washed by either colloid or pentoxifylline wash methods, and the motility parameters were measured at either 37 degreesC or 40 degreesC at baseline (0 hours) and after 4 hour s. Five randomly selected washed specimens with matching 37 degreesC (contr ol) or 40 degreesC heat treatments were assessed for changes in a sentinel gene. RESULTS: The percentage of sperm hyperactive motility was >5 times higher a fter the 40 degreesC heat treatment, in comparison with the 37 degreesC tre atment, for both the colloid- and the pentoxifylline-washed sperm. The perc entages of total motility and progression were equally enhanced in heated s perm for the two wash methods. No changes were detected in the sentinel gen e with the heat treatment. CONCLUSION: Sperm cells mildly heated at 40 degreesC responded with greater motility, progression, and hyperactivation. The data suggest that mild hea t is a stimulus for sperm function because greater sperm hyperactivation is associated with increased sperm fertilizing capacity. The absence of chang e in the sentinel gene in heated sperm suggests that a temperature of 40 de greesC is too low to initiate alterations in the highly condensed sperm chr omatin. More studies are needed before mild heating of ejaculated sperm bec omes acceptable for use in assisted reproductive technologies.