EFFECT OF HIGH-FAT DIET ON SPERM QUALITY EVALUATED BY HETEROLOGOUS BINDING ASSAY OF RABBIT SPERMATOZOA TO ZP-FREE MOUSE OOCYTES

AVENA, V.; FUNES, A; WETTEN, P.A.; KLINSKY LAHOZ, O.G.; MONCLUS, M.; BOARELLI, P; SAEZ LANCELLOTTI, E.; MICHAUT, M.A.; FORNÉS, M.

Mendoza

Congreso; XL REUNIÓN ANUAL DE LA SOCIEDAD DE BIOLOGIA DE CUYO; 2022

Sociedad de Biología de Cuyo

For a sperm to fertilize an oocyte, it must undergo sperm capacitation (Cap), the successive acrosomal reaction (AR), and finally, penetrate the zona pellucida: (ZP) before the fusion of the membranes of both gametes that leads to being incorporated into the ooplasm. Spermatozoa (sp) obtained from hypercholesterolemic rabbits (HCR) by fat diet display alterations in Cap and AR processes. Cholesterol loss is an essential step in sperm capacitation. In previous studies, we observed that HCR spermatozoa have elevated cellular cholesterol, inhibiting this process and AR's subsequent progression. To further explore the fertilization potential of cholesterol-enriched spermatozoa, we performed a binding assay using zp-free mouse oocytes. For this purpose, control rabbits (NCR) and rabbits fed with 7 % (½ HFDR) or 14 % fat (HFDR) were developed. A biochemical monitoring of glycemia, TG, Cholesterol and HDL-Cho was performed. After obtaintion, samples followed three steps: 1) spermogram 2) sperm selection by swim up with BWW medium (0.5% BSA), and 3) incubation for 16 h with HTF medium (0.5% BSA-Cap inducer). In parallel, oocytes were collected from hormonally superstimulated CF-1 mice (8 weeks old). ZP was removed by a brief incubation in Tyrode´s acid, and washed further in HTF medium. Sperm and oocytes, were coincubated for 1 h at 37 °C and 5 % CO2 at a final concentration of 50,000 sp/100 ul. After coincubation, the oocytes were washed in 3 drops of HTF medium to remove unattached sp. Oocytes with bound sperm were fixed with 2% PAF, washed in blocking solution, and mounted on Vectashield containing permeable Hoechst to quantify the number of membrane-bound sp per oocyte. Spermatozoa from HFD-fed rabbits, which had abnormal spermograms, also gave poor binding rates (½ HFDR: 7.14 ± 3.39 and HFDR: 3.28 ± 2.10 sperm per oocyte) compared to control sp (NCR: 32.47 ± 16.16 sperm per oocyte). From these results, we conclude that the ingestion of the high-fat diet in this animal model is associated with a lower sperm binding, which suggests another level in the fertilizing. process in which HFDR sperm are altered.