(+)-Catechin and (-)-epigallocatechin gallate: are these promising antioxidant therapies for frozen goat semen?

English. ABSTRACT The aim of this study was to evaluate the effects of different concentrations of (+)-catechin or (-)-epigallocatechin gallate (EGCG) on goat semen freezability. Poolsof semen were processed (Experiment 1: 0, 15, 25, 50, 75, or 100µM (+)-catechin; Experiment 2: 0, 15, 25, 50, 75, or 100µM EGCG) and frozen. After thawing, the samples were evaluated for kinematics, plasma membrane (PMi) and acrosome integrity, morphology, and oxidative stress, at 0 and 1h. In Experiment 1, at 0h, VSL and VAP were greater (P<0.05) with 15µM than with 50 and 100; WOB was lower (P<0.05) with 100µM than with 0, 15, and 25; and BCF was higher (P<0.05) with 75 and 100µM than with 0. In turn, in Experiment 2, progressive motility was higher (P<0.05) with0 and 15µM than with50 and 75; LIN was lower (P<0.05) with75 and100µM than with0 and 15; WOB was higher (P<0.05) with0 and 15µM; and PMi was greater (P<0.05) with100µM than 0. Thus, (+)-catechin or EGCG at higher concentrations inhibits the kinematics of frozen goat sperm, in a transitory way, and 100µM of EGCG preserves the PMi.

Portuguese. RESUMO Objetivou-se avaliar o efeito de diferentes concentrações de (+)-catequina ou (-)-epigalocatequina galato (EGCG) sobre a congelabilidade do sêmen caprino. Poolsseminais foram processados (experimento 1: 0, 15, 25, 50, 75 ou 100µM de (+)-catequina; experimento 2: 0, 15, 25, 50, 75 ou 100µM de EGCG) e congelados. Após a descongelação, foram avaliadas a cinética, a integridade de membrana plasmática (iMP) e acrossomal, a morfologia e o estresse oxidativo, a zero e a uma hora. No experimento 1, a zero hora, VSL e VAP foram maiores (P<0,05) com 15µM do que com 50 e100; WOB foi menor (P<0,05) com 100µM do que com 0, 15 e 25; e BCF foi maior (P<0,05) com 75 e 100µM do que com 0. No experimento 2, a motilidade progressiva foi maior (P<0,05) com 0 e 15µM do que com 50 e 75; LIN foi menor (P<0,05) com 75 e 100µM do que com 0 e 15; WOB foi maior (P<0,05) com 0 e 15µM; e iMP foi maior (P<0,05) com 100µM do que com 0. Assim, (+)-catequina ou EGCG em altas concentrações inibem, transitoriamente, a cinética de espermatozoides congelados caprinos, e 100µM de EGCG preserva a iMP.