Katz, D. F., Morales, P., Samuels, S. J., & Overstreet, J. W. (1990). Mechanisms of filtration of morphologically abnormal human sperm by cervical mucus. Fertility and sterility, 54(3), 513-516.
Katz DF, Morales P, Samuels SJ, Overstreet JW. Mechanisms of filtration of morphologically abnormal human sperm by cervical mucus. Fertil Steril. 1990;54(3):513-516.
Katz, David F., et al. "Mechanisms of filtration of morphologically abnormal human sperm by cervical mucus." Fertility and sterility, vol. 54, no. 3, 1990, pp. 513-516.
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It is well known that cervical mucus restricts penetration of morphologically abnormal human sperm, both in vitro and in vivo. However, the mechanisms of such restriction are not well understood. Using videomicrography to simultaneously analyze the motions and morphology of individual human sperm, we analyzed differential penetration of normal and abnormal sperm into fresh human cervical mucus. Abnormal sperm swam slower in mucus than the normal sperm, but their flagellar beat parameters were not commensurately different. Multivariate statistical analysis of the relationship between individual sperm velocity and flagellar beat parameters indicated that the heads of the abnormal sperm experienced greater resistance from the mucus than did normal heads. Differential mucus resistance, more than altered motile vigor, appears to be responsible for the restriction of abnormal sperm during migration through mucus.
Chen C et al., 2005·Environ Health Perspect·Free full text on PubMed Central
Our recent study showed a dose-response relationship between environmental tobacco smoke (ETS) and the risk of early pregnancy loss. Smoking is known to affect female reproductive hormones. We explored whether ETS affects reproductive hormone profiles as characterized by urinary pregnanediol-3-glucuronide (PdG) and estrone conjugate (E1C) levels. We prospectively studied 371 healthy newly married nonsmoking women in China who intended to conceive and had stopped contraception. Daily records of vaginal bleeding, active and passive cigarette smoking, and daily first-morning urine specimens were collected for up to 1 year or until a clinical pregnancy was achieved. We determined the day of ovulation for each menstrual cycle. The effects of ETS exposure on daily urinary PdG and E1C levels in a +/-10 day window around the day of ovulation were analyzed for conception and nonconception cycles, respectively. Our analysis included 344 nonconception cycles and 329 conception cycles. In nonconception cycles, cycles with ETS exposure had significantly lower urinary E1C levels (beta = -0.43, SE = 0.08, p < 0.001 in log scale) compared with the cycles without ETS exposure. There was no significant difference in urinary PdG levels in cycles having ETS exposure (beta = -0.07, SE = 0.15, p = 0.637 in log scale) compared with no ETS exposure. Among conception cycles, there were no significant differences in E1C and PdG levels between ETS exposure and nonexposure. In conclusion, ETS exposure was associated with significantly lower urinary E1C levels among nonconception cycles, suggesting that the adverse reproductive effect of ETS may act partly through its antiestrogen effects.
Chlamydia trachomatis infection is one of the most common sexually transmitted diseases. Its effect on male fertility, however, is still controversial. In this study, 284 male partners of infertile couples consulting the Center of Studies in Reproductive Biology (CEBRE) were analyzed. The incidence of C. trachomatis infection among male partners of infertile couples was 38.6%. There were no significant differences between infected and noninfected infertile men in any of the sperm parameters assessed (sperm concentration, motility and morphology). The results of the three bioassays developed to evaluate sperm physiology, namely spermatozoa-zona pellucida binding, acrosome reaction stimulated with human follicular fluid and zona-free hamster oocyte penetration, showed no differences between infected and noninfected men. Electron microscopy studies suggest that spermatozoa are active agents in the dissemination of the chlamydial infection; they could be acting as 'vehicles' for the pathogens. These, and other results, suggest that the possible effect of C. trachomatis on male fertility is not due to alterations in sperm 'quality' or function, but rather to the transmission of the disease to female partners, causing inflammatory processes and promoting the generation of antisperm antibodies.
To determine whether the surgical diagnosis of endometriosis can be predicted using symptoms, signs, and ultrasound findings. Prospective study (study sample); retrospective record review (test sample). Hospital of Desio (study sample) and Mangiagalli Hospital (test sample), Italy. PATIENT(S): Ninety women scheduled to undergo laparoscopy or laparotomy (study sample); 120 women who underwent laparoscopy (test sample). The study sample group was interviewed before surgery about infertility and dysmenorrhea, dyspareunia, and noncyclic pelvic pain and each member had a pelvic examination and a transvaginal ultrasound. At surgery, endometriosis was noted. For the test sample, the same information was abstracted from medical records after laparoscopy. MAIN OUTCOME MEASURE(S): The ability of symptoms, signs, and ultrasound to predict endometriosis at surgery. A classification tree was developed with the study sample and evaluated with the test sample. RESULT(S): Ovarian endometriosis, but not nonovarian endometriosis, could be reliably predicted with noninvasive tools. Ultrasound and examination best predicted ovarian endometriosis, correctly classifying 100% of cases with no false positive diagnoses in the study sample. Similar results were found in the test sample. CONCLUSION(S): Noninvasive tools may be used to identify women with ovarian, but not nonovarian endometriosis, with excellent agreement with surgical diagnosis.
The mechanism by which GnRH increases sperm-zona pellucida binding in humans was investigated in this study. We tested whether GnRH increases sperm-zona binding in Ca(2+)-free medium and in the presence of Ca(2+) channel antagonists. We also examined the GnRH effect on the intracellular free Ca(2+) concentration ([Ca(2+)](i)). Sperm treatment with GnRH increased sperm-zona binding 300% but only when Ca(2+) was present in the medium. In Ca(2+)-free medium or in the presence of 400 nM nifedipine, 80 microM diltiazem, or 50 microM verapamil, GnRH did not influence sperm-zona binding. GnRH increased the [Ca(2+)](i) in the sperm in a dose-dependent manner. The maximum effect was reached with 75 nM GnRH. The GnRH-induced increase in [Ca(2+)](i) was fast and transient, from a basal [Ca(2+)](i) of 413 +/- 22 nM to a peak value of 797 +/- 24 nM. The GnRH-induced increase in [Ca(2+)](i) was entirely due to a Ca(2+) influx from the extracellular medium because the increase in [Ca(2+)](i) was blocked by the Ca(2+) chelator EGTA and by the Ca(2+) channel antagonists nifedipine and diltiazem. These antagonists, however, were not able to inhibit the progesterone-activated Ca(2+) influx. On the contrary, T-type calcium channel antagonists pimozide and mibefradil did not affect GnRH-activated Ca(2+) influx but inhibited the progesterone-activated Ca(2+) influx. Finally, the GnRH-induced Ca(2+) influx was blocked by two specific GnRH antagonists, Ac-D-Nal(1)-Cl-D-Phe(2)-3-Pyr-D-Ala(3)-Arg(5)-D-Glu(AA)(6)-GnRH and Ac-(3,4)-dehydro-Pro(1),-p-fluoro-D-Phe(2), D-Trp(3,6)-GnRH. These results suggest that GnRH increases sperm-zona binding via an elevation of [Ca(2+)](i) through T-type, voltage-operated calcium channels.
The important role of cervical mucus from a reproduction standpoint is the transport and selection of spermatozoa. The study of the fertilizing ability of human spermatozoa by the use of zona-free hamster oocytes has shown that morphologically abnormal sperm can fuse with the zona-free hamster oocyte. The high proportion of morphologically abnormal spermatozoa present in human semen is significantly reduced after sperm migration through cervical mucus. The mucus, while a favorable environment for sperm survival, does not seem to contribute to the occurrence of sperm capacitation and acrosome reaction.
The cervical canal mucus is important to human fertility since conception can only occur if sperm pass through the contents of the cervical canal to reach the ovum. The biophysical properties of the cervical mucus and their relation to sperm migration are, therefore, curcial. A variety of laboratory experimentation methods have been used in studies of cervical mucus: 1) sperm migration measurements; 2) reheological studies; 3) cell countings; 4) crystallization studies; 5) Nmr: 6) EPR; and 7) photoelectron spectroscopy. Cervical mucus is the end result of complicated biosynthetic processes occurring in the epithelial cells of the cervical mucosa; this biosynthesis is regulated by many factors. Type E, characteristic for estrogenic stimuli on mucus biosynthesis, and type G, for gestagenic stimulation, are the 2 main types of cervical secretions. The 2 types always occur together, in differing proportions. For example, at normal ovulation there is a 97:3 ratio of type E to type G; at normal corpus luteum, the ratio is 10:90. The string variety of type E seems to aid in conveying sperm from the vagina while the loaf variety is inactive. The very low viscosity of the string variety intermicellar fluid permits very rapid sperm swimming. Not much is known regarding cervical mucus pathology or therapy.
Cervical mucus is produced throughout the menstrual cycle. Sperm migration, however, is possible only during the periovulatory period of the cycle. Cervical mucus is also produced during the amenorrhoeic post-partum period. Post-partum mucus is very similar to luteal phase mucus except that it can allow sperm migration. In this study, mucus samples obtained from all these periods were classified according to their capacity to allow sperm migration. The biochemical characteristics of mucus samples that did (peri-ovulatory and 40% of post-partum samples) and did not (luteal and 60% of post-partum samples) allow sperm migration were then compared. Mucus samples with positive sperm migration showed the highest percentage of water and lowest protein and glycoprotein concentration (per ml of mucus). In addition, post-partum mucus samples with positive sperm migration showed lower concentrations of proteins and glycoproteins than post-partum mucus samples that did not allow sperm migration. However, the amount of glycoproteins per mg of protein was similar between post-partum samples that were positive and negative for sperm migration. These data suggest that the carbohydrate composition of the glycoproteins is playing a key role in the ability of cervical mucus to accept spermatozoa.
Two main types of cervical mucus have been described during the menstrual cycle: oestrogenic and progestative. Each category shows diverse morphological and functional features from the reproductive point of view. Traditionally, this change has been approached by analysing morphological patterns. In fact, a mesh model has been described for cervical mucus, structurally composed of fibrillar subunits with a parallel orientation, together with another model in a characteristic network shape with canalicular units, but the real model is not clear. The objective of our work was to study the different morphological structures of the mucus, as related to the day of follicular rupture (considered as day 0) determined by ultrasound. Cervical mucus samples were obtained from the cervical canal with an ASPIRETTEtrade mark from day -4 to day +1 of the menstrual cycle. Samples were fixed and dried by critical point. The ultrastructure was examined with scanning electron microscopy. The presence of three types of oestrogenic and one type of progestative cervical mucus was confirmed in this period. Our paper shows different types of ultrastructure in the oestrogenic mucus in relation to ovulation, which would help to understand the interaction between male gametes and cervical mucus in migration through the female genital tract.
