Location: Warmwater Aquaculture Research UnitTitle: Effects of melatonin or maternal nutrient restriction on vascularity and cell proliferation in the ovine placenta
|EIFERT, ADAM - West Virginia University|
|WILSON, MATTHEW - West Virginia University|
|VONNAHME, KIMBERLY - North Dakota State University|
|CAMACHO, LETICIA - North Dakota State University|
|BOROWICZ, PAWEL - North Dakota State University|
|REDMER, DALE - North Dakota State University|
|ROMERO, SINIBALDO - North Dakota State University|
|DORSAM, SHERI - North Dakota State University|
|HARING, JODIE - North Dakota State University|
|LEMLEY, CALEB - North Dakota State University|
Submitted to: Animal Reproduction Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/29/2014
Publication Date: 2/1/2015
Citation: Eifert, A.W., Wilson, M.E., Vonnahme, K.A., Camacho, L.E., Borowicz, P.P., Redmer, D.A., Romero, S., Dorsam, S., Haring, J., Lemley, C.O. 2015. Effects of melatonin or maternal nutrient restriction on vascularity and cell proliferation in the ovine placenta. Animal Reproduction Science. 153:13-21.
Interpretive Summary: In the pregnant ewe, placental vascularity was not associated with uteroplacental blood flow. Dietary melatonin and nutrient restriction decreased caruncle vascularity, while chronic uterine infusion of melatonin did not alter placental vascularity.
Technical Abstract: Previously we reported increased umbilical artery blood flow in ewes supplemented with melatonin from mid- to late-pregnancy, while maternal nutrient restriction decreased uterine artery blood flow. To further unravel these responses, this study was designed to assess placental cell proliferation and vascularity following supplementation with melatonin or maternal nutrient restriction. For the first experiment, 31 primiparous ewes were supplemented with 5 mg of melatonin per day (MEL) or no melatonin (CON) and allocated to receive 100% (adequate fed; ADQ) or 60% (restricted; RES) of their nutrient requirements from d 50 to 130 of gestation. To examine melatonin receptor dependent effects, a second experiment was designed utilizing 14 primiparous ewes infused with vehicle, melatonin, or luzindole (melatonin receptor 1 and 2 antagonist) from d 62 to 90 of gestation. For experiment 1, caruncle concentrations of RNA were increased in MEL-RES compared to CON-RES. Caruncle capillary area density and average capillary cross-sectional area were decreased in MEL-RES compared to CON-RES. Cotyledon vascularity was not different across dietary treatments. For experiment 2, placental cellular proliferation and vascularity were not affected by infusion treatment. In summary, melatonin interacted with nutrient restriction to alter caruncle vascularity and RNA concentrations during late pregnancy. Although melatonin receptor antagonism alters feto-placental blood flow, these receptor dependent responses were not observed in placental vascularity. Moreover, placental vascularity measures do not fully explain the alterations in uteroplacental blood flow.