The effect of heparin, caffeine and calcium ionophore A 23187 on in vitro induction of the acrosome reaction in frozen-thawed bovine and caprine spermatozoa

The effect of heparin (5 IU), caffeine (5 mM) and calcium-ionophore A23187 (0.1 mM) on motility and in vitro induction of the acrosome reaction in gla ss wool filtered frozen-thawed bull and goat semen was studied. The motile spermatozoa fraction was obtained after glass wool filtration of frozen-tha wed semen. The seminal plasma was removed from filtered semen by centrifuga tion, and the sperm pellet was resuspended in Sperm-TALP medium. Samples of treated and untreated control semen of both species were incubated at 37 d egrees C. At 1, 15 and 30 min of incubation the proportions of progressivel y motile and acrosome-reacted spermatozoa were assessed. Trypan blue and Gi emsa stain was used to differentiate live and dead spermatozoa having under gone acrosome reaction. Glass wool filtration enhanced the proportion of mo tile spermatozoa from 43% to 62% in the bovine and from 41% to 60% in the c aprine. Whereas the effect of incubation with caffeine, heparin and calcium -ionophore on spermatozoan motility was negligible, the treatment of semen with calcium-ionophore resulted in a significantly improved percentage of l ive spermatozoa with true acrosome reaction at all stages of incubation, bo th in the bovine and the caprine. (C) 2000 by Elsevier Science Inc.