EX VIVO PROGRESSION OF SPERMATOGENESIS CONCURS WITH THE EXPRESSION OF GENE INVOLVED IN LIPID METABOLISM AND C22-PUFA GENERATION

AVELDAÑO, M.I.; SANTIAGO VALTIERRA, F.X.; LUQUEZ, J.M.; ORESTI, G.M.

Reunión virtual por pandemia COVID-19

Congreso; XXXI Reunión Anual Virtual Sociedad Chilena de Reproducción y Desarrollo; 2020

Spermatogenesis can progress ex vivo in neonatal mouse testes using a gas-liquid interphase culture system. Previously we observed in vivo a relationship between the progression of spermatogenesis and the gene expression of some of the enzymes involved in fatty acid and lipid biosynthesis, concomitant with the generation of the corresponding lipid products. The aim of this study was to examine, in cultured testis explants, the expression of two PUFA elongases (Elovl2 and Elovl4), delta-6-desaturase (Fads2), fatty acid 2-hydroxylase (Fa2h), two fatty acid binding proteins (Fabp3 and Fabp9) and a diacylglycerol acyltransferase (Dgat2) and evaluate the changes in total lipid and glycerophospholipid fatty acid composition. Testis explants from 6 day old mice cultured for 22 days evidenced a progress in spermatogenesis beyond the meiotic phase in some of the tubules. The appearance of haploid germ cells concurred with an increase in the expression of Fabp9, Dgat2 and Fa2h. Notably, genes involved in PUFA biosynthesis (Elovl2, Elovl4, Fads2) and transport (Fabp3) were up-regulated in the testicular explants in comparison with the in vivo situation. Concomitantly, the proportion of major C22 PUFA (22:4n-6, 22:5n-6, 22:5n-3 and 22: 6n-3) increased in the glycerophospholipids of explants. Like in vivo, the 22:5n-6/20:4n-6 ratio increased with ex vivo development, and 22:5n-6 was the major PUFA of total testicular lipid after 22 days of culture. The data are consistent with specific PUFA elongations and desaturation [20:4n-6-->22:4n-6-->22:5n-6] being activated during germ cell differentiation ex vivo.Supported by SGCyT UNS-PGI-UNS [24/B272 to GMO], FONCyT, [PICT2017-2535 to GMO].