SEMEN OF SPINAL-CORD INJURED MEN FREEZES RELIABLY

The objectives of the present study were to: 1) determine the effect o f cryopreservation on the percent and the grade of motility of sperm f rom spinal cord injured (SCI) men and 2) determine which method of fre ezing yields the best post-thaw motility in sperm from SCI men. Antegr ade semen samples were obtained from 9 SCI subjects and 10 age-matched healthy control subjects. Motility in fresh samples was determined an d cryopreservative medium was added to each sample. Aliquots of each s ample were frozen according to three methods: 1) liquid nitrogen vapor only (V); 2) vapor for 12 minutes followed by submersion into liquid nitrogen (V+N2); and 3) direct submersion into liquid nitrogen (N2). S amples were frozen for 1 week, then thawed. The post-thaw percent and grade of motility was determined. The mean percent motility of fresh s amples for SCI subjects (21.0%) was significantly lower than that for control subjects (55.7%). After thawing, the mean percent drop in moti lity for V, V+N2, and N2 for controls was 65.2%, 73.5%, and 79.4%, res pectively, and for SCI subjects, it was 64.7%, 74.5%, and 81.6%, respe ctively. There was no statistically significant difference between con trol and SCI subjects by method of freezing. Vapor only as a freezing method was superior to all other methods for retention of sperm motili ty in both control and SCI subjects. We conclude that the semen of SCI men may be frozen reliably and that their sperm retain motility simil ar to that of normal men. Vapor only, being the most gentle method use d, gives the best recovery of sperm motility in either group. D