Apoptosis and related proteins during parturition in prostaglandin F receptor-deficient mice

Vaginal Probiotic Lactobacillus crispatus Seems to Inhibit Sperm Activity and Subsequently Reduces Pregnancies in Rat

Background

The vaginal microbiota is associated with the health of the female reproductive system and the offspring. Lactobacillus crispatus belongs to one of the most important vaginal probiotics, while its role in the agglutination and immobilization of human sperm, fertility, and offspring health is unclear.

Methods

Adherence assays, sperm motility assays, and Ca²⁺-detecting assays were used to analyze the adherence properties and sperm motility of L. crispatus Lcr-MH175, attenuated Salmonella typhimurium VNP20009, engineered S. typhimurium VNP20009 DNase I, and Escherichia coli O157:H7 in vitro. The rat reproductive model was further developed to study the role of L. crispatus on reproduction and offspring health, using high-throughput sequencing, real-time PCR, and molecular biology techniques.

Results

Our results indicated that L. crispatus, VNP20009, VNP20009 DNase I, and E. coli O157:H7 significantly inhibited the sperm motility in vitro via adversely affecting the sperm intracellular Ca²⁺ concentration and showed a high adhesion to sperms. The in vivo results indicated that L. crispatus and other tested bacteria greatly reduced the pregnancy rates, but L. crispatus had a positive effect on maternal health and offspring development. Moreover, the transplantation of L. crispatus could sustain a normal bacterial composition of the vaginal microbiota in healthy rats and markedly reduced the expression of uterine inflammatory factors (toll-like receptor-4/nuclear factor kappa-B, tumor necrosis factor-α, production of interleukin-1β, etc.) and apoptosis factors (Fas Ligand, Bcl-2-associated X protein/B cell lymphoma-2, etc.) compared with the other tested strains.

Conclusion

Our study demonstrated that the vaginal probiotic L. crispatus greatly affected the sperm activity and could also reduce pregnancies through its adhesion property, which might account for some unexplained infertility. Therefore, more caution should be paid when using L. crispatus as a vaginal viable preparation in women of child-bearing age, especially for women whose partners have abnormal sperms.

Conditional loss of ERK1 and ERK2 results in abnormal placentation and delayed parturition in the mouse

Extracellular-signal-regulated kinases (ERK) 1 and 2 regulate many aspects of the hypothalamic-pituitary-gonadal axis. We sought to understand the role of ERK1/2 signaling in cells expressing a Cre allele regulated by the endogenous GnRHR promoter (GRIC-ERKdko). Adult female GRIC-ERKdko mice were hypogonadotropic and anovulatory. Gonadotropin administration and mating led to pregnancy in one-third of the ERKdko females. Litters from ERKdko females and pup weights were reduced coincident with delayed parturition and 100% neonatal mortality. Based on this, we examined Cre expression in implantation sites as a potential mechanism. GnRHR mRNA levels at e10.5 and e12.5 were comparable to pituitary levels from adult female mice at proestrus and GnRHR mRNA in decidua was enriched compared to whole implantation site. In vivo studies confirmed recombination in decidua, and GRIC-ERKdko placentas showed reduced ERK2 expression. Histopathology revealed abnormalities in placental architecture in the GRIC-ERKdko animals. Regions of apoptosis at the decidual/uterine interface at e18.5 were observed in control animals but apoptotic tone in these regions was reduced in ERKdko animals. These studies support a potential model of ERK-dependent signaling within the implantation site leading to loss of placental architecture and mis-regulation of apoptotic events at parturition occurring coincident with prolonged gestation and neonatal mortality.

Apoptosis and related proteins in placenta of intrauterine fetal death in prostaglandin f receptor-deficient mice

The present study investigated whether the increase of apoptosis in the placenta is associated with intrauterine fetal death in prostaglandin F receptor-deficient mice. Apoptosis was demonstrated within placental and decidual tissue by the TUNEL method. The majority of apoptosis was found in syncytiotrophoblast tissues. Enhanced TUNEL-positive staining in the syncytiotrophoblast layer was scattered in the placental tissues in clusters of apoptotic cells in the death group. Marked TUNEL-positive cells were identified in decidua of both groups. The rate of apoptosis in the placenta and decidua in the death group was higher than that in the survival group (P < 0.05). Immunohistochemical analysis showed that the level of active caspase-3 protein expression in the placenta in the death group was much higher than that in the survival group. The level of Bcl-2 protein expression in the placenta in the death group was much lower than that in the survival group. Western blot analysis demonstrated that increased expression of the active form of caspase-3 was detected in the placenta and decidua in the death group compared with that in the survival group. In contrast, a decrease in the expression of Bcl-2 was detected in the placenta and decidua in the death group compared with that in the survival group. Enhanced expression of Bax:Bcl-2 ratio was detected in placenta and decidua in the death group compared with that in the survival group. Thus, significantly increased apoptosis in the mouse placenta and decidua might be involved in the pathophysiologic mechanism of intrauterine fetal death.