Quantitation of nexus junctions in the granulosa cell layer of rabbit ovarian follicles during ovulation

Electron microscopy was used in a semi-quantitative study to determine changes in the abundance and size of surface nexuses and changes in the abundance of interiorized nexuses in growing and mature ovarian follicles during the ovulatory process. Mature follicles contain larger granulosa cells than follicles in the early stage of antral formation. Also, the granulosa cells of mature follicles have a slightly greater number of surface nexuses (without a change in nexus length), and more interiorized nexuses, compared to immature follicles. As a mature follicle approaches rupture, there is an appreciable decrease in the number of surface nexuses per granulosa cell. There is also a slight reduction in the number of interiorized nexuses at this time. It is concluded that this decrease in both surface nexuses and interiorized nexuses may be a consequence of ovulatory changes during which the rate of granulosa cell division is greater than the rate of formation of new nexuses. Additionally, the disruption to cell-to-cell cohesion during the ovulatory process appears to be independent of the interiorization of surface nexuses.