Detection of Fas ligand in the bovine oviduct

Dynamics of apoptosis-related gene expression during follicular development in yak

The potential reproduction power of domestic animals is limited by a complicated follicular atresia process. P53, caspase-9 (Casp9), Bax, Bcl-2 and Fas play a crucial role in the ovarian mitochondrion-dependent apoptosis and death receptor pathway. In accordance with this study, the expression levels of Casp9, Bax, Bcl-2 and Fas were analysed in ovaries and oviducts of yak by immunohistochemistry (IHC). P53 and the above in ovarian granulosa cells (GCs) from atretic (3-6 mm) to healthy follicles (6-8 mm) and in oviducts were examined from the luteal phase to the follicular phase during the oestrous circle by Western blot (WB) and real-time PCR (RT-PCR). Results demonstrated that typical classic apoptotic factors Casp9, Bax, Bcl-2 and Fas were expressed in the cytoplasm and zonal pellucida of oocytes, primordial follicles, primary follicles, ovarian surface epithelium, ovarian GCs, granular lutein cells, surface epithelia in oviduct uterotubal junction and oviduct ampulla during the luteal phase. RT-PCR and WB revealed that P53 and Fas significantly increased in GCs of atretic follicles. P53 and Casp9 increased in oviduct epithelium during the luteal phase, but Fas was unchanged. A contrary tendency was noted in Bcl-2 and Bax expression. Overall, P53 and Fas play an essential role in inducing GC apoptosis, and Bax, Bcl-2, Casp9 and P53 are involved in oviduct epithelial regeneration in yak.

Corticosterone induced apoptosis of mouse oviduct epithelial cells independent of the TNF-α system

It has been reported in recent studies that restraint stress on pregnant mice during the preimplantation stage elevated corticotrophin-releasing hormone (CRH) and glucocorticoid levels in the serum and oviducts; furthermore, CRH and corticosterone (CORT) impacted preimplantation embryos indirectly by triggering the apoptosis of oviductal epithelial cells (OECs) through activation of the Fas system. However, it remains unclear whether TNF-α signaling is involved in CRH- and/or glucocorticoid-induced apoptosis of OECs. In the present study, it was shown that culture with either CRH or CORT induced significant apoptosis of OECs. The culture of OECs with CRH augmented both FasL expression and TNF-α expression. However, culture with CORT increased FasL, but decreased TNF-α, expression significantly. Although knocking down/knocking out FasL expression in OECs significantly ameliorated the proapoptotic effects of both CRH and CORT, knocking down/knocking out TNF-α expression relieved only the proapoptotic effect of CRH but not that of CORT. Taken together, our results demonstrated that CRH-induced OEC apoptosis involved both Fas signaling and TNF-α signaling. Conversely, CORT-induced OEC apoptosis involved only the Fas, but not the TNF-α, signaling pathway. The data obtained are crucial for our understanding of the mechanisms by which various categories of stress imposed on pregnant females impair embryo development, as well as for the development of measures to protect the embryo from the adverse effects of stress.

Spinal cord biological safety of image-guided radiation therapy versus conventional radiation therapy

Tumor models were simulated in purebred Beagles at the T_9-10 levels of the spinal cord and treated with spinal image-guided radiation therapy or conventional radiation therapy with 50 or 70 Gy total radiation. Three months after radiation, neuronal injury at the T_9-10 levels was observed, including reversible injury induced by spinal image-guided radiation therapy and apoptosis induced by conventional radiation therapy. The number of apoptotic cells and expression of the proapoptotic protein Fas were significantly reduced, but expression of the anti-apoptotic protein heat shock protein 70 was significantly increased after image-guided radiation therapy compared with the conventional method of the same radiation dose. Moreover, the spinal cord cell apoptotic index positively correlated with the ratio of Fas/heat shock protein 70. These findings indicate that 3 months of radiation therapy can induce a late response in the spinal cord to radiation therapy; image-guided radiation therapy is safer and results in less neuronal injury compared with conventional radiation therapy.

The vanguard sperm cohort of the boar ejaculate is overrepresented in the tubal sperm reservoir in vivo

In boars, sperm cohorts are sequentially emitted in epididymal cauda fluid and resuspended in different mixtures of accessory sex gland secretions while ejaculated in various fractions. During natural mating, these ejaculate fractions sequentially enter the cervix-uterine lumen, are quickly transported towards the tips of the uterine horns and colonize the oviductal sperm reservoirs (SR). Using a simple experiment, we tested the hypothesis that the first ejaculated sperm subpopulation (fortuitously present in the peak portion of the sperm-rich fraction [SRF], the so-called Portion 1, P1) is, by reaching first the SR, overrepresented there. Spermatozoa from P1- and of P2- (last portion of the SRF and the Post-SRF) were collected from 3 fertile boars. P1-spermatozoa were fluorophore DNA-stained, while P2-spermatozoa were kept unstained. Weaned estrous sows were conventionally inseminated (12 h after onset of estrus) with similar sperm numbers (approx 10 x 10(9) spermatozoa) per portion but in different orders as follows: (i) a mix of P1 and P2 aliquots (control, P1+P2, n=5), or testing (ii) a sequential order (P1-P2, Treatment A, n=5) or (iii) an inverse order (P2-P1, Treatment B, n=5) of cohort AI. Sows were euthanized approx 3 h post-AI, and the SRs were flushed to recover the spermatozoa, which were accounted for as stained or unstained. The total number of spermatozoa flushed did not differ between groups or boars (NS, ranging 0.9 to 2.0 x 10(9)). Sequential, in vivo-like, sperm deposition (P1-P2, Treatment A) yielded the highest proportion of stained P1-spermatozoa in the SRs (59.8 +/- 5.66%, means +/- SEM) compared with when the order was reversed (P2-P1, Treatment B; 15.6 +/- 2.1% P1-spermatozoa, P<0.05) or P1 and P2 sperm suspensions were mixed (control, 36.9 +/- 2.70% P1-spermatozoa, P<0.05). The tested hypothesis proved valid; if inseminated in the same order as ejaculated in vivo, P1-spermatozoa become overrepresented in the SR. The physiological consequences of this skewed SR-colonization are discussed in this paper alongside the advantageous use of P1-spermatozoa for handling, including cryopreservation.

Effect of retinoic acid on apoptosis and expression of Fas proteins in mouse blastocysts cultured in vitro

Mouse blastocysts were exposed to doses of 0, 1 and 10 micromol/L retinoic acid (RA) for 24 h and the cytotoxic effect of RA on the mouse blastocysts in vitro was observed. FITC-labeled terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL-FITC) assay was employed to stain apoptotic cells and immunohistochemical S-P staining method was used to detect the expression of Fas protein in mouse blastocysts in vitro. The results showed that RA could induce apoptosis and increase the expression of Fas proteins of trophectoderm (TE) and inner cell mass (ICM) cells in blastocysts. Compared with the findings for the control blastocysts, exposure to RA (10 micromol/L) resulted in a more significant apoptosis and higher expression level of Fas proteins (P<0.01). It was concluded that RA could induce apoptosis, which may result in a significant reduction in the average number of total cells and the trophectoderm/inner cell mass in blastocysts and an increased expression of Fas protein, suggesting that RA had a cytotoxic effect on the growth and development of early embryos in mice.

The influence of pre- and post-ovulatory insemination and early pregnancy on the infiltration by cells of the immune system in the sow oviduct

The aim of this study was to investigate the influence of pre- and post-ovulatory insemination and early pregnancy on the distribution of immune cells in the oviduct. Eighteen sows were pre-ovulatory and sixteen sows were post-ovulatory inseminated and slaughtered at different times, 5-6 h after insemination, 20-25 h and approximately 70 h after ovulation, day 11 and day 19. Immediately after slaughter, oviductal samples of three different segments (isthmus, ampulla and infundibulum) were fixed, embedded in plastic resin and stained with toluidine blue or cryofixed and stored in a freezer at -70 degrees C until analysed by immunohistochemistry (pre-ovulatory inseminated sows) with an avidin-biotin peroxidase method. Quantitative and qualitative examinations of oviductal epithelium and subepithelial connective tissue were performed by light microscopy. After pre- or post-ovulatory insemination, neutrophils were not observed in the oviductal epithelium from any of the segments or groups. The numbers of intraepithelial lymphocytes of all sows as well as CD2- and CD3-positive cells of the pre-ovulatory inseminated sows were higher in the infundibulum than in the other segments (p < or = 0.001). In the subepithelial connective tissue of the pre-ovulatory inseminated sows, significantly higher numbers of lymphocytes (p < or = 0.001) and plasma cells (p < or = 0.001) were found in infundibulum than in isthmus. Neutrophils were found mainly in infundibulum, the number approximately 40 h after pre-ovulatory insemination was significantly higher (p < or = 0.05) than in the other groups and segments. Significantly higher numbers of CD2 than CD3-positive cells were found for all groups and segments. In the subepithelial connective tissue of post-ovulatory inseminated sows, the numbers of lymphocytes was higher (p < or = 0.001) at day 19 than up to 50 h after insemination and lower (p < or = 0.001) in isthmus than in ampulla and infundibulum. Neutrophils were found in infundibulum in almost all groups and the number was significantly higher (p < or = 0.05) in the infundibulum up to 50 h after insemination than in other segments. In the oviductal epithelium, no influence of insemination was found on the presence of phagocytes, i.e. neutrophils and macrophages, but on lymphocytes. In the infundibular connective tissue, pre-ovulatory insemination had an effect on neutrophil distribution, indicating an active immune response to insemination in the upper segment. Post-ovulatory insemination changed the oviductal immune cell pattern.