Endometrial blood perfusion as assessed using a novel laser doppler technique in Angus cows

Authors: OWEN, MEGAN - Mississippi State University; MCCARTY, KEELEE - Mississippi State University; HART, CAITLIN - Mississippi State University; STEADMAN, CHRISTY - Mississippi State University; LEMLEY, CALEB - Mississippi State University

Submitted to: Animal Reproduction Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/29/2018
Publication Date: 2/1/2018
Citation: Owen, M., McCarty, K., Hart, C., Steadman, C., Lemley, C. 2018. Endometrial blood perfusion as assessed using a novel laser doppler technique in Angus cows. Animal Reproduction Science. 190:119-126.

Interpretive Summary: There are no minimally invasive or non-terminal techniques to acquire endometrial perfusion data in livestock species, which led to the objective of the present study: validating laser Doppler to examine endometrial perfusion of cattle in relation to total endometrial nitrite concentrations during the estrous cycle. Endometrial blood perfusion was greatest mid-estrous cycle and on the same side of the corpus luteum as well as endometrial concentrations of nitric oxide, which support the validity of this novel technique for assessing endometrial perfusion in cattle. Collection of endometrial perfusion data provides for the ability to gather localized blood flow information which could have future implications for treatments to improve uterine involution during the post-partum period or for utilization of this technique during breeding soundness exams for female livestock.

Technical Abstract: Previous studies have characterized ovarian steroid synthesis which directly affects uterine environment and blood flow. Clearance of steroids occurs primarily in hepatic tissues, however, it was discovered that there is an abundant activity of the phase II steroid metabolizing enzyme UDP-glucuronosyltransferase (UGT) in uterine biopsies. No minimally invasive techniques for collecting endometrial perfusion, which is affected by steroids and indicative of reproductive health, have been developed for livestock. The objective of the present study was to characterize UGT activity and endometrial blood perfusion during a normal estrous cycle of cattle. It was hypothesized that there would be increased steroid metabolism during the luteal phase of the estrous cycle and in the uterine horn ipsilateral to the corpus luteum (CL). During the first synchronized estrous cycle, progesterone and UGT activity increased on Day 6 compared with 0 and 3, with the first day of estrus being considered Day 0 of the study. Endometrial perfusion was greater ipsilateral to the CL compared with contralateral on Day 12, and was less ipsilateral to the CL compared with contralateral on Day 18. Similar to perfusion results, nitric oxide metabolites (nitrites) were greatest in the endometrium ipsilateral as compared with contralateral to the CL. Moreover, there was a positive correlation (r=0.28; P=.04) between endometrial perfusion and nitrite concentration. It is concluded that activity of UGT within the endometrium is affected by the contralateral or ipsilateral location of the CL, and collection of endometrial perfusion data using a laser Doppler probe could be a viable measurement technique as indicated by associated nitrite concentrations in the present study.