Sperm chemotactic activity induced by the oocyte-cumulus complex in the rabbit

GUIDOBALDI, HA; TEVES, ME; UÑATES, DR; GIOJALAS, LC

Giessen, Alemania

Workshop; 4th International Wokshop "Molecular Andrology"; 2005

In mammals, sperm chemotaxis towards follicular fluid has been observed in human, mouse and rabbit spermatozoa. In humans, both the egg and the cumulus oophorus secrete chemoattractants. The aim of this work was to identify the sources of attractants in the rabbit. Rabbit females were mated to stimulate the growth of the follicles. Nine hours post coitus, and before ovulation, the ovaries were surgically removed. Conditioned media from the: oocyte-cumulus complex (OC), oocyte (0), and cumulus (C) were obtained after 48-h cell culture in Ml99 medium. Sperm samples were obtained with artificial vagina and capacitated for 16 h in BWW. The chemotactic activity of several dilutions of the condition media was determined in a chemotaxis chamber by videomicroscopy and computer image analysis. BWW and bovine FF (1:104) were assayed as negative and positive controls, respectively. The conditioned medium of OC showed sperm chemotactic activity at 1 and 0.1 OC/ml dilutions, with values similar to the positive follicular fluid control. In addition, no changes where observed in the pattern of movement nor in the sperm speed. When the C conditioned medium was assayed, a significant sperm chemotactic response was observed at 5 C/ml, at an extent similar to the positive follicular fluid. Preliminary experiments showed no significant chemotactic signal in the presence of the O conditioned medium. We conclude that (i) both the oocyte-cumulus complex and the isolated cumulus secrete at least one sperm chemoattractant; (ii) the O conditioned medium apparently does not secrete chemoattractants in the rabbit; however, additional experiments are required to confirm the latter results.