[Scanning electron microscopic study on corrosion casts for rabbit ovarian follicle microvasculature during the...

The microvasculature of rabbit ovarian follicles were investigated three-dimensionally with resin casting/SEM technique during ovulation and corpus luteum formation. The basic vascular pattern around Graafian follicles remains essentially unchanged, except for expansion of the blood vessels to keep pace with follicle growth, until ovulation occurs. The resin leaked out from the inner capillary wreath and could not get into the apical vessels just prior to ovulation. These findings indicate the increased capillary permeability and congestion of blood stream at the apical region shortly before ovulation. At 3-5 hours after ovulation, the unusually dilated vessels were developed into the follicular cavity, and then the fine vessels in radiating arrangement sprouted from the theca capillary wreath in one or two days. There seems to be regulatory roles of vascular systems in ovulatory and luteinizing process.