Contact of dog spermatozoa with homologous uterine tube epithelium prolongs flagellar activity in relation to the stage of the estrous cycle

There is scant information about the storage of spermatozoa within the repr oductive tract of the bitch. In several species the uterine tube plays a si gnificant role in sperm storage. The present study was performed to investi gate the interaction between spermatozoa and the epithelium of the uterine tube, in particular how this interaction might influence the flagellar acti vity of spermatozoa in relation to the stage of the estrous cycle. Epithelium was harvested from uterine tubes of 24 bitches at various stages of the estrous cycle (estrus, luteal phase or anestrus), and cultured with pooled spermatozoa collected from 6 dogs. Spermatozoa rapidly bound to the epithelial surface by their heads and the majority of attached spermatozoa were motile. The intimate association between spermatozoa and the uterine tube epithelium maintained motility in a manner that was related to the sta ge of the estrous cycle. Flagellar activity was significantly greater for s permatozoa bound to estrous epithelium than epithelium from the luteal phas e or anestrus. On average, approximately 10% of spermatozoa that were attac hed to the uterine tube epithelium of estrous bitches retained their flagel lar activity for 48 h after innoculation. There was no apparent influence o f the region of the uterine tube on this effect. These findings suggest tha t the uterine tube may form a functional spermatozoal reservoir in the bitc h. (C) 2000 by Elsevier Science Inc.