EFFECT OF CRYOPROTECTIVE ADDITIVES AND CRYOPRESERVATION PROTOCOL ON SPERM MEMBRANE LIPID-PEROXIDATION AND RECOVERY OF MOTILE HUMAN SPERM

Sperm membrane damage during cryopreservation reduces the recovery of motile sperm. The present study investigates changes in sperm motility and membrane lipid peroxidation (LPO) in response to two changes in t he standard sperm cryopreservation/ thawing methodology: 1) the additi on of platelet-activating factor (PAF) and pentoxifylline (PTX) as cry oprotective additives, and 2) the alteration of sample thawing time. P AF(1 mu M) and PTX (3 mM) were added to fresh sperm samples prior to c ryopreservation. After 2 weeks the Samples were thawed either quickly (5 minutes at 37 degrees C) or slowly (30 minutes at 4 degrees C) and evaluated for sperm motility and LPO. Thawing time influenced both pos t-thaw motility and LPO. Samples thawed quickly exhibited a 31% increa se in motility recovery (35.2+/-4.3% in quick-thaw samples; 24.3+/-3.9 % in slow-thaw samples) and a 23% lower LPO level (23.3+/-3.4% in quic k-thaw samples; 30.09+/-4.4% in slow-thaw samples) compared to samples thawed slowly. Results also demonstrated that PAF(49+/-1.7%) or PTX ( 42.6+/-1.5%) enhance post-thaw motility in comparison to control (35.3 +/-1.2%), whereas neither PAF nor PTX affect postthaw LPO(19.1+/-2.2% in controls; 20.2+/-1.7% in PAF samples; 26.5+/-1.4% in PTX samples). These results support observations that there is a negative correlatio n between sperm motility and LPO in cryopreserved samples. The results also discount the hypothesis that I-PO protection is a result of the cryoprotective action of PAF or PIX.