Computational multivariate modelling of electrical activity of the porcine uterus during spontaneous and hormone‐induced oestrus

Abstract

New Findings What is the central question of this study?Does oestrous cycle synchronization influence myoelectrical activity of porcine myometrium? What is the main finding and its importance?Exogenous hormones used to synchronize oestrus in pigs altered myoelectrical activity, which was effectively modelled. Higher‐order multivariate statistic modelling provided evidence of similar activity in both types of oestrus, but a larger order of EMG signals during induced oestrus. Higher‐order statistical analysis of the probabilistic model suggests the beginning of the early follicular phase and the mid‐luteal phase to be most important in evaluation of the natural patterns of myoelectrical activity. Higher‐order multivariate cumulants are more informative than classical statistics in characterization of myoelectrical activity changes in porcine myometrium. Abstract In pig production units, control of the oestrous cycle and synchronization of ovulation have become routine herd management procedures. During the oestrous cycle, in both induced and spontaneous conditions, the ovaries and the uterus undergo hormone‐dominated physiological changes, which are consistent with the hypothesis that there is a functional role of uterine contractions in promoting fertilization. We have used electromyography to determine whether the use of exogenous hormones, such as equine chorionic gonadotrophin and human chorionic gonadotrophin, which have the potential to control the timing of ovulation in female pigs, changes the multivariate relationships between parameters of electrical bursts and modulates the patterns of myoelectrical activity. We used the mathematical approach of higher‐order multivariate cumulants in complex modelling of the myometrial electrical activity. The experiment was conducted on 12 mature Polish Landrace sows, and uterine activity was recorded during both spontaneous and induced oestrous cycles. The burst parameters were determined using six features in the time domain and, after Fast Fourier transformation, in the frequency domain. Evaluation of myoelectrical activity patterns was conducted based on classical univariate statistical methods and multivariate probabilistic modelling. The classical statistical approach indicated weaker myoelectrical activity after hormonal stimulation, whereas the higher‐order multivariate statistical model showed evidence of similar status of activity and a larger order of signals during induced oestrus. Routine oestrous cycle synchronization affects the multivariate probabilistic model of myometrial electrical activity.

Uterus Modeling From Cell to Organ Level: Towards Better Understanding of Physiological Basis of Uterine Activity

“…In vivo, ex-vivo and in-virtro data have been used for developing model and/or model validation. Data were always recorded noninvasively from a living person or sometimes invasively from animals so as to obtain useful signals with less noise [47], [48]. Subsequently, the studies on uterus modeling at different levels are reviewed, from cellular level, at which the generation of action potential and/or force is described.…”

“…Although most models have been developed for contributing to the human beings, animal models were also taken into consideration with in vivo invasive recording which contains less noise and produces additional crucial information about uterine activity [32], [47]. Domino et al considered porcine uterus as a reference model for preclinical study and indicated its high applicability [47], [48]. Wu et al performed MRI scan and surgery on Karahdin sheep, whose abdomen size is similar as that of humans.…”

“…3 with λ i the deviatoric efined by λ i ¼ J À1=3 λ i , where J is the total volume ratio and λ i are the principal stretches. odel, we chose a density of 950 kg m and monitor uterine contractions as well as discover the source and propagation of uterine electrical activity for assisting in prediction of problematic labors [1], [24]- [29], [31]- [33], [47], [48], [52], [54], [55], [66], [77], [84]. One of the models contains not only the uterus but also the foetus in order to study the uterine contractions during the expulsion of foetus [33].…”

Selected Methods for non-Gaussian Data Analysis

“…Using the analogical approach in [241] authors have applied higher order culuants tensors to analyse features of the EMG signal of the estrus cycle in pigs. Here, in contrary to the classical statistical approach, the higher order cumulants tensors model shows evidences of large EMG activity during induced estrus.…”

“…This is in contrary to the spontaneous estrus. Authors of [241] concludes, that higher order cumulants tensors are indicator revealing a probabilistic model of dynamic changes in the myometrial electrical activity as a result of positive and negative feedback of the reproductive hormones.…”