Doppler Ultrasonography for Live Imaging and Quantification of Ovarian Vascular Function in Mice

To effectively assess ovarian vascular function and understand its role in ovarian physiology and pathology, non-invasive in vivo approaches are essential for capturing real-time changes without disrupting normal blood flow. Doppler ultrasonography is a well-established, non-invasive tool for assessing ovarian blood flow in larger species, but its application has been limited in mice, which are one of the most widely used animal models for research in ovarian biology, such as ovulation. Ovulation is a tightly regulated process that depends on coordinated follicular maturation stimulated by follicle-stimulating hormone, followed by a preovulatory luteinizing hormone (LH) surge that leads to rupture of the follicle wall and release of oocytes for fertilization. The LH surge also triggers a series of structural and functional changes in the ovarian vasculature (vascular remodeling), such as angiogenesis and constriction of capillaries at the follicular rupture site shortly before ovulation. In addition, a rapid increase in ovarian blood flow following the LH surge has been reported in multiple species but not in mice. This protocol utilizes Doppler ultrasonography to visualize the murine ovarian vasculature and quantify hemodynamic parameters. The protocol presented here reports detailed methods for hormone priming, anesthesia, positioning of the mouse, identification of the ovary and its vasculature using power and color Doppler, and measurement of blood flow velocity and resistance parameters. This method enables real-time, longitudinal assessment of ovarian vascular function in live mice, providing a powerful tool for studying ovarian vascular function in both physiological and pathological contexts.