Effects of semen thaw-refreeze by standard vapor freezing method on human sperm motility, viability and morphology. Fertility & Sterility, vol. 80, Suppl. 3,pág. 228-9, September 2003. Trabalho apresentado no 59º Congresso Americano de Medicina Repro

P-321 Effects of semen thaw-refreeze by standard vapor freezing method on human sperm motility, viability and morphology. Sandro C. Esteves, M.

F. R. Venturini, S. Verza Jr. ANDROFERT-Centro de Referência em Infertilidade Masculina, Campinas, Brazil. Objective: To evaluate the suitability of thaw-refreeze human semen by using the standard freezing method.

Design: Semen specimens frozen by standard vapor freezing were thawed at room temperature for 5 minutes and at 37°C for 20 minutes. An aliquot was removed for sperm analysis and the remaining specimen was refrozen by standard vapor freezing without removing the cryomedia (TEST-yolk buffer with glycerol, Irvine, USA). The specimens were stored in liquid nitrogen for 48h and re-thawed by the same technique. An aliquot was removed for sperm analysis and the remaining specimen was discharged.

Materials and Methods: Twenty frozen semen samples were obtained from 16 subjects (cancer patients, n _ 6 and male infertility patients enrolled in an ART program, n _ 10) who required disposal of their samples stored in our sperm bank. Each sample was evaluated for motile sperm count, percent and progressive motility, viability and morphology (strict criteria). Wilcoxon signed-rank test was used to test for statistical differences in sperm parameters.

Results: There was a significant decrease in all sperm parameters after the thaw-refreeze process. Motile sperm count, percent sperm motility, progressive sperm motility, viability and morphology decreased from 5.8 million/ mL to 1.9 million/mL (P _ 0.01), 38.3% to 20.2% (P _ 0.01), 28.4% to 11.5% (P _ 0.01), 38.7% to 19.3% (P _ 0.01), and from 5.3% to 4.3%, respectively. There was no difference between cancer and ART patients regarding the outcome of the refreeze-thaw process.

Conclusion: Normal and viable motile sperm can be obtained after thaw-refreeze sperm using the standard vapor freezing method. The number of good quality spermatozoa are adequate for in vitro fertilization using intracytoplasmic sperm injection. Therefore, leftover frozen-thawed specimens can be refrozen for future use. This approach has benefits specially for cancer patients who urge to start the chemotherapy/radiotherapy and cannot freeze multiple specimens.