Date of Award

Spring 5-11-2018

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Animal Sciences

Advisor

Robert Causey

Second Committee Member

Martin Stokes

Third Committee Member

Mary Tyler

Abstract

Bacterial uterine infections inflict major losses on the equine breeding industry. These infections usually arise from bacteria introduced at breeding. Micro-currents propelled by ciliated cells between the folds of the uterus and cervix have been proposed as a means by which contaminants are expelled. Previous data have shown possible ciliary micro-currents propelling carbon particles, occasionally rotating, through cervical folds. However, adherence to the epithelium may have interfered with movement of carbon in these studies. Therefore, we tested potentially non-adherent substances to reveal ciliary micro-currents on the equine cervix under high magnification video-endoscopy. We hypothesized that polyethylene green microspheres 1 - 5 μm and 50 μm in diameter, would be superior to carbon in revealing micro-currents on the cervical epithelium and that 50 μm hemispherically coated bichromal microspheres would display rotation. A suspension containing these microspheres and carbon was deposited onto the cervix of 5 estrous mares and movement of each type of particle was recorded under high video endoscopy for approximately 10 - 20 minutes. In more than 50% of each video recording the field of view was obscured by camera movement or poor positioning. However, the remainder of the recording contained short segments in which the interactions between the epithelium and particles were observable. All observable segments were then analyzed for the presence or absence of desired (visibility, motion, and rotation) and undesired (aggregation) criteria for each type of particle. Particles were scored for the prevalence of these desired and undesired criteria according to the number of video segments in which they were observed. Data were analyzed by the Kruskal-Wallis test. Backward rotation of bichromal spheres was interpreted as evidence of ciliary activity. Overall, carbon scored equal to or higher than the microspheres, leading to rejection of the hypothesis. Of the microspheres, the bichromal microspheres scored highest overall, but tended to aggregate more than the green microspheres, aggregation being undesirable. Subjective assessment concluded that cervical movement was closely related to respiratory movements of the mare, and that the constantly moving cervical folds helped clear the deposited particles. These data may improve detection of mucociliary clearance in the cervix and uterus and may assist future studies to detect impaired mucociliary clearance in infertile mares.

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