Sperm Migration through the Human Female Reproductive Tract

Transcription

1 Sperm Migration through the Human Female Reproductive Tract HERBERT W. HORNE, JR., M.D., and JEAN-PAUL THIBAULT, M.D. 0 ALTHOUGH the vagina is the natural receptacle for semen, from which the sperm penetrate the cervical mucus, their survival in the vagina is of brief duration. Confirming Masters' earlier report of seeing live sperm in the vagina for hours after coitus, the authors also consider the vaginal secretions a hostile environment, to be left behind by the sperm as rapidly as possible. MacLeod and Sobrero have observed sperm in the cervical mucus less than 1 min. after ejaculation. Under optimum conditions, the mucus is so ''hospitable" that sperm have been seen by the authors and others to survive as long as 96 hours after insemination. Harvey, on the basis of the speed of sperm in favorable cervical mucus, states that they could enter the tubes by their own locomotion within half an hour of insemination. Does the cervix play a strictly passive role during sperm migration or does it actively participate, in addition to producing mucus through its glands? Amersbach, using a cervical cap containing inert carbon particles, recovered some particles from the fundal cavity after coitus had taken place with the cap in place. Recently Egli and Newton have reported on the rapid transmission into the tubes of carbon particles which were placed in the vagina in a Dextran suspension prior to hysterectomy. This transmission was aided, perhaps, by the simultaneous intramuscular injection of 1 cc. of oxytocin. The findings of Kelly are very pertinent. These observations, if later confirmed by others, make it difficult to explain the apparent similarity in conception rates of women who do and those who do not reach orgasm. It raises the question as to whether stimulation of the cervix by coitus is alone enough to cause oxytocin outflow even in the absence of orgasm. And how does the uterus know when to contract when simple donor insemination into the vagina is performed? Certainly much more remains to be learned if there are factors other than simple sperm migration. Some consideration has been given in the literature to factors which may *Research Fellow, Fertility and Endocrine Clinic, Boston Lying-in Hospital, Boston, Mass. 135

2 136 HORNE & THIBAULT FERTILITY & STERILITY give upward direction to the progression of sperm, but very little has been substantiated. Balin has described increased activity and speed of propulsion of sperm exposed to follicular, tubal, and peritoneal fluids. The authors have also seen a similar increase with the use of amniotic fluid. Balin suggests that the tubal and follicular fluids which probably proceed down the genital tract at ovulation cause a speeding up of the sperm as they ascend, thus effectively providing a directing mechanism upward for the more rapid progress toward the waiting egg. In spite of Bickers' statement 3 that sperm cannot ascend into the fundal cavity without uterine contractions, Frenkel found that the sperm concentration in the fundal cavity was greatest during the ovulatory phase, and that few invade the fundus during the secretory phase. From the fundus, sperm must enter the intramural tube and, from there, progress upward. Yamanaka and Soderwall have shown in the hamster that the number of sperm entering the oviducts is exceedingly small compared with the number present in the cornua. In the nulliparous human female, the intramural portion of the tube is markedly tortuous and has a very small lumen. In the multipara, probably secondary to the stretching caused by previous pregnancies, this part of the tube has become straightened and appears to be more widely patent. Horstmann and Vasen have described the muscular coats of the tube and have shown that each continues into the myometrium without interruption. These presumably form a functional sphincter which, during peristalsis, propels the sperm upward and the conceptus downward into the fundal cavity. Kneer and Cless, observing in vitro the action of cilia in the human salpinx, found that tiny particles such as spermatozoa were wafted to and fro, becoming dispersed evenly over the lining of the tube. However, larger particles such as ova, which were directly in contact with the folds of the mucosa, moved toward the uterus. Borel showed in the rat and rabbit that ciliarv movement is increased at ovulation time. It is suggested that the ciliary a~tion thus directs the sperm upward, abetting the increased speed of propulsion caused by the tubal and follicular juices previously mentioned, while the peristaltic action of the musculature propels the conceptus downward. Rubenstein, from hysterectomy specimens, showed that motile sperm were present in the tubes within half an hour after coitus and that they were still present after 50 hours. In 1949, Hertig and one of us (H. W. H.), during the search for the 60-hour-old two-celled conceptus which was found in the middle third of the tube, also saw viable sperm moving in the tubal washings. Clewe and Mastroianni have demonstrated in the rabbit that tubal secretions are dependent on estrogen and progesterone secretion. Noyes has shown, in the rabbit, at least, that tubal juice is necessary to sperm for activating their ability to fertilize. The work of Shettles suggests this may also be true in the human. Doyle states that in the human there is a rapid pickup of the follicular fluid at the time of ovulation and infers that it is this "vacuum cleaner" action of the tube at ovulation that picks up the ovum in the human.

3 VoL. 13, No.2, 1962 SPERM MIGRATION 137 It must be admitted that the anatomical conditions in the rabbit, where an effective ovisac causes immediate delivery of the ovum into the tube for fertilization, are different from the tubovarian mechanism in the human. Further, although we were all taught that human conception occurs in the tube, as it indeed does in the rabbit andlower animals, to date we have no actual proof that the human ovum, with its approximately 12 hours of conceivability, must necessarily be in the tube to be fertilized. Instead, it is possible that conception in the human may occur in the peritoneal cavity, with the conceptus then being picked up by the tube after conception. Some rationale for this possibility is found both in Doyle's work and that of Decker, who placed starch granules of ovum size in the cul-de-sac and found them in the cervix the next day. However, the authors can find no report that viable sperm have been described in peritoneal fluid, except for mention by one of us (H. W. H.) of this fact in a previous publicationp Since we now have repeatedly substantiated the presence of sperm in the peritoneal fluid, the case for intra-cul-de-sac conception is a bit more plausible. It suggests that a smooth cul-de-sac may be important as a place for ovum and sperm to meet and that a cul-de-sac which is deeply divided into compartments (as a result of endometriosis) may be a real deterrent to fertilization and to the pickup of the conceptus by the tube. In the hope of stimulating in others interest in the investigation of this unorthodox concept, we present a new test that may shed further light on the mechanisms of sperm migration in the human and that may also be a means of prognosticating the chances for subsequent conception in patients undergoing sterility laparotomies. Our results, though still meager, conclusively prove that sperm do in fact live in the peritoneal fluid of the cul-de-sac where perhaps the human ovum finds its first temporary home after leaving the follicle. MATERIAL AND METHOD Ideally, these experiments should have been performed on women known to be fertile. The group of patients used, however, was composed of those with long-standing infertility who, therefore, may have had other etiological factors complicating the picture. Surgery was advised mainly for endometriosis andjor peritoneal adhesions as seen at previous culdoscopy, when the complete fertility study of both partners had proved unfruitful. Patients with clear-cut intrinsic tubal disease were not included. The purpose of the experiment was to determine in each case whether, 24 hours after coitus at ovulation time, sperm could be found in the peritoneal fluid from the cul-de-sac and in tubal washings. Each patient was scheduled for an operation to coincide with expected ovulation and was asked to have coitus the morning of admission. A postcoital test was performed 24 hours later before premedication was administered, following which laparotomy was performed, with careful exclusion of blood from the peritoneal cavity.

4 138 HORNE & THIBAULT FERTILITY & STERILITY The ever-present cul-de-sac fluid was aspirated before exploration. Subsequent to freeing the tubes, tubal washings were obtained separately by lavage from below with indigo-carmine saline solution through a previously placed Jarcho cannula. The specimens so obtained were then centrifuged. It has been found recently that adding a small amount of heparin to the tubes before collection keeps the fluid from clotting, as occasionally occurs. The supernatant was decanted, and a small drop of the sediment was placed on a slide and covered with a coverslip. Scanned under low-power magnification the always-present red blood cells were seen to be "jumping." Higher magnification disclosed the cause of the jumping to be the flailing tail of a sperm progressing through the lightly packed red cells. We add parenthetically that we are just now beginning to examine cul-de-sac fluid obtained at culdoscopy. RESULTS As may be seen in Table 1, among 14 cases in which postcoital insemination was either good or fair, 5 patients were found to have sperm in the peritoneal fluid and 9 had sperm in the tubal washings. No patient has become pregnant, but one had a probably early loss at 5 weeks after ovulation as suggested by basal temperature record, but without microscopic proof. Followup since laparotomy is too brief in most cases to have allowed for conception to take place. DISCUSSION In addition to the reports cited above, many others have appeared concerning the basic questions of how sperm proceed upward and the conceptus is TABLE 1. Data for Spenn Found in Tubal and Peritoneal Fluid at Laparotomy Duration of infertility (mo.) Right Left Caae tube tube Peritoneum Primary Secondary TOTAL Av. 48 Av. 34

5 VoL. 13, No.2, 1962 SPERM MIGRATION 139 propelled downward. It is evident that no clear-cut understanding of these mechanisms has been reached. Whether the cervix, fundus, and tubes form a passive conduit system through which the sperm migrate under their own locomotion or, whether they actively take part is still unclear. The present investigation may lead to new information and to a reappraisal of our long-held concepts of sperm migration and of tubovarian function in the human. Eventually this may help to clarify the many unknown factors surrounding the meeting of the human sperm and ovum. It must be kept clearly in mind that the human female reproductive tract is both anatomically and physiologically different from those of lower animals, and that the mechanisms and chemistry of the fluids described for the lower animals may not hold true for the human. Continued study at both levels will undoubtedly lead to a real understanding of many of the unknowns of human infertility. SUMMARY A brief outline is given of the presently held concepts of sperm penetration upward through the human female reproductive tract. The commonly held fact that human conception occurs in the tube is questioned. Confirmation is given of the presence of motile sperm in the peritoneal fluid at the time of laparotomy. A preliminary report of the finding of sperm in the peritoneal fluid in 5 of 14 cases at the time of sterility laparotomy is presented. 221 Longwood Ave. Boston 15, Mass. REFERENCES 1. AMERSBACH, R. Munchen med. Wchnschr. 77:225, BALIN, H. Am. ]. Obstet. & Gynec. 76:30, BICKERS, W. Fertil. & Steril. 11:286, BoREL, V., et al. Acta obst. et gynec. scandinav. 86:22, CLEWE, T., and MASTROIANNI, L. ]. Reprod. & Fertil.1:146, DEcKER, A. Obst. & Gynec. 4:35, DoYLE, J. Fertil. & Steril. 5:105, EGLI, G., and NEWTON, M. Fertil. & Steril. 12:151, FRENKEL, D. (In Press). 10. HARVEY, C. ]. Reprod. & Fertil. 1:84, HARVEY, C., et al. ]. Reprod. & Fertil. 1:157, HoRNE, H., and AUDET, C. Obst. & Gynec. 11:421, HoRSTMANN, E. Z. Zellenforsch. 87:415, KELLY, J. Fertil. & Steril. (In Press). 15. KNEER, M., and CLEss, H. Geburtsh. u. frauenh.11:233, SoBRERO, A., and MAcLEon, J. Fertil. & Steril. (In Press). 17. MASTERS, W. The 35th Ross Conference on Pediatric Research, 1961, p NoYEs, R. W., et al. ]. Endocrinol. 17:374, RUBENSTEIN, B., et al. Fertil. & Steril. 2:15, SHETTLES, L. B. Fertil. & Steril. 6:287, V ASEN, L. Int. ]. Fertil. 4:309, YAMANAKA, H., and SonERWALL, A. Fertil. & Steril. 11:410, 1960.