Simple vitrification for small numbers of human spermatozoa

Abstract

Cryopreservation of human spermatozoa has now become a routine procedure in assisted reproductive technology. In cases of severe male infertility, intracytoplasmic sperm injection (ICSI) is a treatment option with high success in IVF and oocytes can be fertilized by ICSI even if spermatozoa have poor motility or are frozen ( Craft et al., 1993 x Craft et al., 1993 Craft, I., Bennett, V., and Nicholson, N. Fertilising ability of testicular spermatozoa. Lancet. 1993; 342: 864 Abstract | PubMed | Scopus (162) | Google Scholar See all References , Palermo et al., 1992 x Palermo et al., 1992 Palermo, G., Joris, H., Deveroey, P., and Van Steirteghem, A. Pregnancies after intracytoplasmic sperm injection of single spermatozoon into an oocyte. Lancet. 1992; 340: 17–18 Abstract | PubMed | Scopus (2379) | Google Scholar See all References ). In cases of azoospermia, cryopreservation of testicular spermatozoa can avoid repeated testicular biopsy and it is useful for effective treatment and management ( Schelgel and Su, 1997 x Schelgel and Su, 1997 Schelgel, P.N. and Su, L.M. Physiological consequences of testicular sperm extraction. Hum. Reprod. 1997; 12: 1688–1692 Crossref | PubMed | Scopus (327) | Google Scholar See all References Schelgel and Su, 1997 ). Since the first attempts at human sperm cryopreservation ( Bunge and Sherman, 1953 x Bunge and Sherman, 1953 Bunge, R.G. and Sherman, J.K. Fertilizing capacity of frozen human spermatozoa. Nature. 1953; 172: 767–768 Crossref | PubMed | Scopus (122) | Google Scholar See all References Bunge and Sherman, 1953 ), many studies have been devoted to the development of optimal freezing techniques for human spermatozoa. However, traditional freezing techniques are not suitable for spermatozoa from the testis because of their low number and poor in-situ motility ( AbdelHafez et al., 2009 x AbdelHafez et al., 2009 AbdelHafez, F., Bedaiwy, M., El-Nashar, S.A., Sabanegh, E., and Desai, N. Techniques for cryopreservation of individual or small numbers of human spermatozoa: a systematic review. Hum. Reprod. Update. 2009; 15: 153–164 Crossref | PubMed | Scopus (41) | Google Scholar See all References AbdelHafez et al., 2009 ). The lack of an easily implemented technology has remained a major bottleneck for the cryopreservation of small numbers of spermatozoa.