Uterine Rhythms: navigating the changes during the estrus cycle

The uterus remains understudied in its normal function. Hormonal fluctuations, driven by the menstrual cycle (humans) or estrus cycle (non-menstruating mammals), significantly influence uterine activity. My thesis combined experimental data and mathematical modelling to describe changes in uterine anatomy and electrophysiology throughout the estrus cycle in rats. This presentation will cover the anatomical and electrical variations in the rat uterus during the estrus cycle, and present mathematical models of rat uterine electrophysiology. High-resolution micro-computed tomography (𝜇CT) was used to capture rat uterine muscle anatomy at different cycle stages. From these scans, anatomical variations were quantified and muscle fibre orientations extracted using structure tensors. Electrical activity was recorded in vivo using high-resolution electrode arrays. The electrical signals were processed to characterise the frequency and duration of events, and the propagation patterns and velocities across the estrus cycle. A mathematical model of the non-pregnant rat uterine smooth muscle cell was developed from an existing pregnant model, including new progesterone and estrogen components which was then embedded in a continuum model of whole organ function. This work provides novel methods for anatomical assessment of the uterus, high-resolution mapping of uterine electrical activity, and mathematical modelling of the electrophysiology of the non-pregnant rat uterus.