Effect of cryoprotective media and freezing techniques on human semen preservation

With the growing programme of IVF--Et at Lagos University Teaching Hospital the need arise to establish a sperm bank to meet the ever increasing demand at the Hospital for artificial inseminations and in-vitro fertilisation. Fifteen semen samples with count range 50--200 million/ml and motility 30--82% were used. The effectiveness of five synthetic cryoprotectants I, II, III, IV and V and three freezing techniques A, B, and C in cryoperserving human semen were studied. The results were assessed by comparing prefreeze and post thaw sperm motility. Our results using ANOVA (analysis of variance) demonstrated that (1) 7.5% glycerol produced better results than all the other cryoprotectants. (2) Initial freezing in ultralow electrical freezer (-90 degrees c) before storage in liquid nitrogen (-196 degrees c) produced a significantly better post-thaw motility and this was maintained for 4 weeks (table 2). It was therefore concluded that sperm banking can be accomplished in a relatively simple and reliable way using 7.5% glycerol alone and initial freezing in ultralow electrical freezer before storage in liquid nitrogen.