Influences of intrauterine semen administration on regulatory T lymphocytes in the oestrous mare (Equus caballus).

In the mare, early pregnancy loss is common, but involvement of the maternal immune system in the pathogenesis of this condition has not been investigated in detail so far. In the present study, we assessed effects of exposure of the endometrium to semen or seminal plasma in oestrous mares on the response of regulatory T lymphocytes (Tregs) in the peripheral circulation as well as in the endometrium. Raw semen, seminal plasma or PBS (control) were introduced into the uterus of oestrous mares (n = 12). Blood was collected immediately before insemination or PBS infusion (time 0), and 12, 24 and 48 h thereafter. Endometrial biopsies were collected at 24 h. In peripheral blood, Treg (CD4+Foxp3+) cells were determined by flow cytometry. In endometrial biopsies, Tregs were assessed as cells staining positive for Foxp3 by immunohistochemistry. The percentage of Tregs in blood decreased (p < 0.05) at 12 h after exposure to seminal plasma, tended to decrease in response to raw semen (p = 0.095) but not to PBS. Leukocyte and PMN counts were not affected. In the endometrium, numbers of Foxp3 positive cells at 24 h after insemination or PBS infusion were not changed by treatment. Results of the present study provide only little evidence that maternal tolerance of pregnancy in the horse is modulated already by exposure of the oestrous endometrium to seminal plasma at mating.

Multidimensional gas chromatography methods for bioanalytical research.

Multidimensional gas chromatography (MDGC) methods are high-resolution volatile chemical separation techniques, and comprise classical heart-cutting MDGC and its more recent incarnation, comprehensive 2D GC. Although available for a long period, MDGC approaches are still not widely practiced in the field of bioanalysis, possibly reflecting the general preference for regular GC versus MDGC approaches. With the recent introduction of '-omic' techniques that emphasize global nontargeted profiling of metabolites within living systems, it is evident that MDGC is gaining momentum as a separation tool, since it offers very high resolution. By untangling metabolites within highly complex biological matrices, and expanding the metabolic coverage, MDGC plays a frontline role in '-omics' based studies. This review highlights state-of-the-art MDGC approaches, and summarizes the recent developments in bioanalytics.

Sperm-Activating Odorous Substances in Human Follicular Fluid and Vaginal Secretion: Identification by Gas Chromatography-Olfactometry and Ca2+ Imaging.

Human sperm chemotaxis to follicular fluid has been well established, but the molecular mechanism(s) for this phenomenon are still largely unclear. Studies indicate that odorant receptors expressed on spermatozoa could play a role in this scenario. It has recently been shown that several synthetic floral scents activate the receptors OR1D2, OR4D1, and OR7A5 in vitro and evoke distinct sperm motility patterns in vivo. However, all agonists found so far are of synthetic origin and, thus, the presence of endogenous structural analogues in female bodily fluids is subject to speculation. Therefore, the aim of the study reported herein was to investigate the occurrence of odor compounds in vaginal secretions and follicular fluid by using gas chromatography-olfactometry. Chemically identified constituents of either bodily fluid were then analyzed for activation of recombinant chemoreceptors and candidate ligands were further tested for induction of sperm Ca2+ signals. Through using this approach, two novel odorant receptor-ligand pairs are reported and human sperm Ca2+ elevations in response to both odorous substances, namely 5α-androst-16-en-3-one and 4-hydroxy-2,5-dimethyl-3(2H)-furanone, are shown.