Incorporation of sterols into ram sperm reduces the percentage of acrosome reacted spermatozoa after cryopreservation

CARRO, M.M.; HOZBOR, F.A.; FURLAND, N.E.; PEÑALVA, D.A.; BUSCHIAZZO, J.

Ciudad de Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Cryopreservation of sperm is a useful biotechnological tool for artifcial insemination. However, ram sperm is particularly sensitive to this process, limiting its use for this species. Previously, we found a signifcant sterol loss in cryopreserved ram sperm and a concomitant decrease in membrane lipid order. Recently, we established controlled conditions to increase sperm sterol content using methyl-β-cyclodextrin (MβCD). The objective of this study was to evaluate the impact of increasing cholesterol (Chol) and desmosterol (Des) content of ram sperm (2.5, 10, 25mM MβCD-sterol) on: 1) membrane lipid order and level of the putative raft marker, ganglioside GM1, and 2) sperm quality parameters after thawing. Treatment of semen with 10 and 25mM MβCD-Chol or -Des increased membrane lipid order determined by fluorescence spectroscopy (Laurdan). The presence of GM1 was detected in living sperm using the fluorescent-labeled cholera toxin B subunit. GM1-related fluorescence was mainly associated to the post-acrosomal region and was reduced when both sterols were incorporated into the sperm at 25mM MβCD, suggesting a membrane disorganization effect induced by sterol incorporation (p