Effects of lipopolysaccharide on follicular estrogen production and developmental competence in bovine oocytes.

Reproductive efficiency and female fertility is essential for productive and sustainable beef cattle operations. Gram-negative bacterial infections cause release of the endotoxin lipopolysaccharide (LPS) which initiates immune responses shown to alter ovarian steroidogenesis and impair oocyte development. The current study was designed to investigate the impact of varying levels of naturally occurring infection and follicular LPS on estradiol (E2) production and oocyte maturation. Bovine ovary pairs were harvested from a slaughterhouse, and oocytes were aspirated from small follicles and matured in vitro. Meiotic events were evaluated on nuclear maturation and spindle morphology to classify oocytes as normal or abnormal. Follicular fluid LPS concentrations were measured and subsequently separated into Low or High LPS groups. A marked difference was detected between the percent of abnormal oocytes matured from Low LPS follicles, compared to the percent of abnormal oocytes matured from High LPS follicles (P = 0.1). Follicular E2 concentrations tended to be greater for high LPS follicles (P = 0.1), however, relative abundance of mRNA transcripts for aromatase (P = 0.93) and beta-catenin (P = 0.63) were similar between groups. No changes were detected in Toll-like Receptor 4 (P = 0.15), Myeloid Differentiation Factor-2 (P = 0.61), or cluster of differentiation 14 (P = 0.46) mRNA transcript abundance in follicles with high LPS, compared to low. Therefore, even Low levels of follicular LPS indicating a subacute infection is capable of impacting the ovarian milieu and may represent an unappreciated factor leading to reduced female fertility and decreased cow retention.

Effects of lipopolysaccharide on beta-catenin, aromatase, and estrogen production in bovine granulosa cells in vivo and in vitro.

Diseases resulting from Gram-negative bacterial infection can induce an immune response by releasing a lipopolysaccharide (LPS) endotoxin that may lead to impaired fertility in cows. To evaluate the effects of LPS on follicular dynamics in a subacute inflammatory disease state, 14 Angus heifers (BW = 413 kg±14) were blocked by weight and assigned to vehicle (n = 7) or LPS treated (n = 7) groups. Heifers received subcutaneous injections of saline (CON) or 2.0 µg/kg LPS on d 2, 5, and 8 of a select synch plus controlled internal drug release device (CIDR) follicular wave synchronization protocol. Fifty hours following CIDR withdrawal, ovaries were harvested, and follicular fluid was collected for hormone and LPS analysis. Daily blood samples were collected from d 0 to d 7. Beginning on d 8 blood samples were collected at 0, 16, 24, 32, 40, and 50 h following LPS challenge. Rectal temperatures were recorded prior to treatment and at regular intervals after each LPS challenge. Heifers treated with LPS exhibited mild (+0.5 °C) hyperthermia (P < 0.05) at 3, 4, and 8 h after the initial LPS challenge (d 2) when compared to vehicle-treated controls. Follicular fluid concentrations of estradiol (E2) increased (P = 0.04) in LPS-treated heifers compared to controls (1,595 ng/mL and 808 ng/mL±240, respectively), while follicular fluid progesterone (P4) concentrations did not differ (P = 0.27) between treatment groups. Additionally, LPS concentrations tended to be increased (P = 0.59) in dominant follicles of LPS-treated heifers, but no difference was detected (P = 0.81) in small developing follicles. To further delineate the impact of LPS on ovarian signaling pathways, a granulosa cell line (KGN) was incubated in the presence or absence of LPS (10 µg/mL) for 48 h. Cells were then collected for gene expression and protein analysis. Cells in both treatment groups expressed toll-like receptor 4, myeloid differentiation factor-2 receptor, and CD-14 complex genes required for LPS signaling. Cells treated with LPS exhibited decreased mRNA expression of aromatase (P = 0.03) and beta-catenin (P = 0.02). However, no change (P > 0.10) was detected in abundance of total beta-catenin protein or beta-catenin phosphorylated isoforms at serine 552 or 675. Based on results from this in vivo experiment, these investigators concluded that low doses of LPS can alter E2 concentrations and this effect may be modulated in part through beta-catenin regulation of aromatase transcription.

A comparison of 3 methods of face-bow transfer recording: implications for orthognathic surgery.

PURPOSE: The purpose of this study was to compare the occlusal plane inclination of models mounted using 3 different systems for face-bow transfer with the actual occlusal plane inclination as measured on a cephalometric radiograph. PATIENTS AND METHODS: Twenty-two subjects were enrolled in this study. Three alginate impressions of the maxillary dentition were taken, and 3 stone dental models were produced for each subject. Face-bow recordings were obtained on each subject using the SAM Anatomical Face-bow (Great Lakes Orthodontics Products, Ltd, Tonawanda, NY), the Erickson Surgical Face-bow (Great Lakes Orthodontics Products, Ltd) and a new technique developed by one of the authors (J.G.). For each subject, the dental models were mounted on a SAM articulator using each of the 3 face-bow recordings. Finally, a lateral cephalometric radiograph was obtained for each subject. The occlusal plane inclination was measured on the models and on the cephalometric radiographs. Differences among groups were tested using a 1-way analysis of variance. Bonferroni test was used for post hoc comparison between different pairs of groups. RESULTS: The average occlusal plane inclination using the SAM Anatomical Face-bow was 7.8 degrees +/- 4.2 degrees greater than the actual-a difference that was statistically significant. The mean occlusal plane inclination of the models obtained using the Erickson Surgical Face-bow was 4.4 degrees +/- 2.2 degrees greater than the actual-a difference that was also statistically significant. The mean occlusal plane inclination of the models obtained by the new technique was only 0.9 degrees +/- 1.2 degrees greater than the actual; this difference was not statistically significant. CONCLUSIONS: The new mounting technique is more accurate than the conventional SAM Face-bow or the Erickson Face-bow for reproducing the actual occlusal plane inclination.