Mouse models of infertility due to swollen spermatozoa

Transgenic mice with male infertility, the c-ros knockout (KO) and GPX5-Tag2 transgenic mouse models, are compared. Both exhibit severely angulated sperm flagella explaining the infertility. As angulated spermatozoa are swollen cells, a failure in volume regulation is indicated. Differences between genotypes were also found: caudal spermatozoa from c-ros KO, but not GPX5-Tag2, could fertilise eggs in vitro; flagellar angulation occurred more within the epididymis of GPX5-Tag2 than c-ros KO mice; the osmotic pressure of cauda epididymidal fluid was lower only in GPX5-Tag2 mice; angulation of caudal sperm from c-ros KO, but not GPX5-Tag2 mice, decreased upon demembranation. These observations indicate that GPX5-Tag2 mice express an earlier, more severe defect. Gene chip analyses of the epididymides revealed decreased expression of the CRES (cystatin-related epididymal-spermatogenic) and MEP17 (murine epididymal protein 17) genes in both genotypes. Further analysis could pinpoint genes essential for epididymal regulation of sperm volume, explain infertility and suggest modes of male contraception. (C) 2003 Elsevier Ireland Ltd. All rights reserved.