In vitro modifications on functional activity of mice sperm induced by the addition of ghrelin.

LUQUE EM; TORRES PJ; DE LOREDO N; VINCENTI LM; FIOL DE CUNEO M; MARTINI AC

Córdoba

Jornada; XIV Jornada de Investigación Científica de la Facultad de Ciencias Médicas; 2013

Ghrelin (Ghr) is a peptide that modulates reproductive physiology, linking reproduction with energy balance. The expression of the peptide and its receptor has been reported in testis, prostate and sperm; the presence of Ghr in seminal plasma has also been informed. The aim of our study was to evaluate the in vitro effects of different doses of Ghr (10-7M and 10-9M), with or without the co-administration of an antagonist (Ant: (D-Lys 3) GHRP-6, 10-5M) on sperm functional activity. We evaluated sperm quality (motility, vitality and acrosomal status) of Albino swiss mice epididymal gametes, after 3 and 40 min of incubation, and sperm response to progesterone (i.e. capacitation) after 120 min of incubation. Results were analyzed by repeated measures ANOVA. Ghrelin decreased sperm motility after 3 min of incubation and the antagonist dose of 10-5M was not capable of reversing these deleterious effects (control=54,1±4,3 vs Ghr 10-9M=42,7±6,0; Ghr 10-7M=40,7±5,9; Ghr 10-9+Ant=46,0±5,0; Ghr 10-7M+Ant=44,4±5,4; Ant 10-5M=48,1±6,6; n=8, p<0,05). This was achieved using a higher dose, 10-4M (Ghr 10-9M=46,5±3,9 vs control=60,6±3,5; Ghr 10-9M+Ant=58,7±1,3; Ant=61,0±6,8). Also, after 3 min of incubation, Ghr 10 -9M decreased the percentage of sperm with intact acrosome (control=90,4±1,2 vs Ghr 10-9M=86,7±1,2 y Ghr 10-9M+Ant=86,4±1,5; n=8, p<0,05). Sperm functional activity at 40 and 120 min was not modified. The addition of progesterone to the culture medium (120 min) induced, in all treatments, a significant increase in acrosome reaction. Since Ghr increases intracellular Ca++ concentrations, alterations in the endogenous levels of this ion could be responsible for the effects exerted by Ghr on motility and acrosome integrity (at 3 min of incubation). The absence of modifications at 40 and 120 min, could be attributed to the activation of sperm compensatory mechanisms.