Abstract:
The influence of 2-hydroxypropyl-beta-cyclodextrin (HBCD) exposure onpost-thaw spermatozoa prior to freezing using acrosome integrity and theparameters of motility was studied. Acrosomal status was monitored by means ofFITC-labelled peanut agglutinin, and the motility parameters were assessedusing a computer-assisted sperm motility analysis (CASA) system. Thespermatozoa were exposed to HBCD over a period of 3 h, during which the cellswere slowly cooled from 25 to 5˚C, and then frozen into pellets. Thepercentage of frozen-thawed spermatozoa with intact acrosomes in 40 mMHBCD group was approximately three-fold higher than that of the control. Themotility and progressive motility values of the frozen-thawedspermatozoa were found to increase significantly with increased HBCDconcentrations. On the other hand, further addition of cholesterol-3-sulfateto the BF5 extender containing 20 mM HBCD resulted in a drastic decrease inthe percentage of spermatozoa with intact acrosomes, and decreased motilityand progressive motility, suggesting that cholesterol-sulfate probablycounter-acted the protective action of HBCD. In conclusion, the results of thepresent study indicate that HBCD protected boar spermatozoa againstfreeze-thaw damage, possibly by means of stimulating the efflux ofmembrane cholesterol.