A method for longitudinal microscopic in vivo examinations of morphology, vascularity, and motility in the ovary and the oviduct of the rat.

ABSTRACT

OBJECTIVE: We developed an in vivo model to enable observation of dynamic changes in morphology, vascularity, and motility of the rat adnexa. METHODS: Immature Sprague-Dawley rats (n = 16) were primed with equine chorionic gonadotrophin (eCG;15 IU) followed by human chorionic gonadotrophin (hCG; 15 IU) 48 hours later to induce ovulation. The experiments were performed during prolonged (up to 12 hours) thiobarbiturate anesthesia. During laparotomy the periovarian bursa was retracted, whereafter the oviductal-ovarian complex was submerged into an organ chamber. Water immersion lenses (4x-40x; final magnification up to 810x) enabled detailed observations that were recorded on Beta-SP videotape. RESULTS: Capillary flow was monitored easily. At the level of the follicle, top blood flow velocity variations (8-10 per minute) were observed in the microvasculature. Ovulations were followed in detail, and oocyte-cumulus complexes were seen later in the oviductal ampulla. Regular contractions in the oviduct were synchronous with the oocyte-cumulus complexes moving back and forth in the oviductal lumen over a distance of about 900 microm. These contractions were more frequent (13-16 per minute) in the postovulatory phase compared with the time before ovulation (9-10 per minute). The oviductal contractions were initiated alternately from either end of the ampulla and were accompanied by a denudation of the oocytes, with a stream of cumulus cells seen moving in an abovarian direction in between contractions. CONCLUSION: High-magnification video recording in vivo was useful for capturing microcirculatory events as well as structural and functional changes of the ovary and the oviduct.