In vitro effects of lipopolysaccharides on bovine uterine contractility |
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Authors: | Maraike Wiebe Christiane Pfarrer Lara Górriz Martín Marion Schmicke Martina Hoedemaker Heiner Bollwein Maike Heppelmann |
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Institution: | 1. Clinic for Cattle, University of Veterinary Medicine Hannover Foundation, Hannover, Germany;2. Institute of Anatomy, University of Veterinary Medicine Hannover Foundation, Hannover, Germany;3. Clinic for Animal Reproduction Medicine, University of Zurich, Zurich, Switzerland |
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Abstract: | Metritis is an important disorder in dairy cows during the early postpartum period. Myometrial contractility is a prerequisite for uterine involution; however, very scanty literature is available about the effect of metritis on this process and endocrine responsiveness. This study was aimed to evaluate the effect of inflammation on uterine contractility in vitro, and the inflammation was induced by incubating myometrial strips with lipopolysaccharides (LPS). Myometrial samples were collected from 17 healthy Holstein Friesian cows during caesarean section. Eight longitudinal strips from each cow were incubated in organ baths with LPS concentrations of 0 (LPS0), 0.1 (LPS0.1), 1 (LPS1) and 10 µg/ml (LPS10). Spontaneous contractility and contractility induced by increasing concentrations of oxytocin (10–10 – 10–7 mol/L) were recorded during nine 30-min intervals (T1 to T9). The minimum amplitude (minA), maximum amplitude (maxA), mean amplitude (meanA) and area under the curve (AUC) were calculated for each time interval. LPS had an effect (p ≤ .05) on maxA, meanA and AUC. In T1, myometrial strips incubated with LPS0.1 and LPS1 had higher (p ≤ .05) maxA, meanA and AUC than the strips incubated with LPS0. In T9 without oxytocin, LPS0 led to higher (p ≤ .05) maxA, meanA and AUC than LPS0.1 and LPS1. In T8 and T9 with oxytocin, LPS1 had lower (p ≤ .05) maxA, meanA and AUC than the other LPS concentrations. Interestingly, the results show that LPS has a transient positive effect on myometrial contractility in vitro and that this effect is dependent on LPS concentration and duration of incubation. |
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Keywords: | cattle contractility lipopolysaccharides metritis myometrium uterine involution |
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