Physiology: Sperm numbers and distribution within the human Fallopian tube around ovulation

Abstract

This study aimed to determine the number and distribution of spermatozoa within the human Fallopian tubes around ovulation. Parous women, undergoing total abdominal hysterectomy for menorrhagia, were inseminated with either partner's semen (3/10) or donor semen (7/10). Approximately 18 h later both Fallopian tubes were ligatured into ampullary, isthmic and intramural regions. These were removed and assessed for sperm content by flushing, scanning electron microscopy (SEM) or homogenization. A median of 251 spermatozoa were recovered (range, 79-1386). The number of spermatozoa within each tube was not significantly different. The ovulatory ampulla contained a significantly (P < or = 0.01) larger percentage of spermatozoa than the non-ovulatory ampulla. The number of motile spermatozoa inseminated was not significantly correlated to the number of spermatozoa recovered, but a trend was identified. The time between the onset of the luteinizing hormone surge and hysterectomy was significantly correlated (P < or = 0.01) to the number of spermatozoa within the intramural regions, but not to the tubal sperm distribution. Spermatozoa were not observed, by SEM, bound to the tubal epithelium. These data suggest that, after artificial insemination at least, sperm access to the human Fallopian tube may be controlled, but that ovulation does not affect the redistribution of spermatozoa between tubal regions and that the isthmus does not appear to act specifically as a sperm reservoir.

The impact of sperm DNA damage in assisted conception and beyond: recent advances in diagnosis and treatment

“…They concluded that sperm morphology, motility and concentration reference values could be no more than a guide to reproductive potential, aligning with reports that the (1999) WHO reference values were not clinically predictive (Nallella et al, 2006;Van der Steeg et al, 2011), although it is clearly too soon to judge whether the new WHO values provide a correlation with outcome. Very few (0.0041%) spermatozoa (Williams et al, 1993) reach the site of fertilization in vivo, This is supported by animal data where considerably fewer than 1% of spermatozoa reach the ampulla of the oviduct at the time of fertilization. Thus to expect an analysis of the gross parameters of the whole ejaculate to give strong discriminatory information is not realistic.…”

Problems of sperm fertility: A reproductive biologist's view

“…Even in the rabbit with much larger oviducts than the hamster, only 20-102 spermatozoa are present in the ampulla around the time of fertilization [Overstreet and Cooper 1979]. In humans, less than 500 [Williams et al 1992] or even less than 100 spermatozoa [Morgenstern et al 1966;Williams et al 1993] are found in the ampulla during the estimated time of fertilization. In other words, less than 0.00005% of ejaculated spermatozoa reach the ampulla by the time of fertilization (Table 1).…”

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“…The zona pellucida composed of several glycoproteins (ZP) that differ in number between species [4,38,42,57,79,106] serves to modulate sperm binding and to protect the embryo during early development. Whether or not mammalian spermatozoa respond to chemotactic stimuli is very much open to debate [110]; however there is data to suggest that an odorant receptor gene expressed in the testis may be involved in sperm chemotaxis in humans [90,105]. Progression through the outer layers of the oocyte depends on successive molecular interactions that change sperm physiology step-by step promoting fertilization competence.…”