Sources Of Goat CEEF And Development Of Goat COC Responsiveness To CEEF

As a consequence of the endogenous gonadotropin surge in the preovulatory period, the compacted cumulus cells around the oocyte expand visibly. This phenomenon is named as cumulus expansion or mucification. Cumulus expansion plays an important role on ovulation and fertilization. But this cumulus expansion needs the cumulus expansion enabling factors (CEEF) to induce. The purpose of this paper was to study the sources of goat CEEF and development of goat COC responsiveness to CEEF. We used an interspecies testing system and mouse oocytectomized complexes (OOX) to test CEEF produced by goat oocytes in different stages and other cells in the follicles. And we also researched the reason of the defect of cumulus expansion of COCs from small follicles (0.8-1.5mm).The results showed that:1. The goat cumulus expansion did not require oocyte.2. Goat oocytes in GV stage secreted CEEF, but MII oocytes didn't secrete CEEF. Moreover, Goat oocytes in different GV style had no significant difference in both production and activity of CEEF.3. There was no CEEF in pellucid zone of goat and mouse oocyte, CEEF was secreted by oocyte itself.4. Goat OOX from 2-4mm follicle secreted CEEF but mural granulose cells from 2-4mm follicles could not. Follicular fluid from 2-4mm goat follicles contained CEEF activity that was concentration-dependent, and thus it enabled cumulus expansion in 71% mouse OOX when used at 10% of concentration, but the expansion rate of mouse OOX decreased to 8.3% when the concentration was increased to 70%.5. Goat cumulus cells in both GV and MII stage secreted CEEF, but goat fetal fibroblast cells, spermatogenic cells and oviductal epithelial cells didn't secrete CEEF. Cumulus cells from whether GV stage or MII stage secreted CEEF, but their ability of secreting CEEF significantly reduced with continuous passage and the days of confluence increased.6. Mouse spermatocyte, spermatogonia and sertoli cells acted as male homologous did not secret CEEF, and STO cells did not secrete CEEF too.7. Oocytes and mural granulose cells from 0.8-1.5mm follicles secreted large amount of CEEF , and follicular fluid from 0.8-1.5mm goat follicles contained CEEF activity that was concentration-dependent. However, no matter cultured in the common medium or in the CM conditioned by oocytes derived from 2-4mm follicles or even co-cultured with COCs derived from 2-4mm follicles, the cumulus oophorus around the oocytes derived from 0.8-1.5mm follicles still could not achieve 3 degree expansion.8. The activity of goat CEEF was found to be heat labile and the activity of CEEF was lost in 65℃. However, frozen-thawed goat oocyte-conditioned media still permitted mouse OOX to undergo cumulus cell expansion.