- Volume 15 Issue 3
The objective of this study was to identify a follicular fluid ingredient inhibiting the cumulus oocyte complex (COC) expansion. Thus, follicular fluid or liquid chromatographic fractions of follicular fluid was supplemented in COC culture medium. And COCs were incubated for 48 hours to investigate about cumulus expansion and also the first polar body extrusion. The results obtained were as follows; 1. The fluid of medium follicle significantly inhibited the COC expansion. 2. The fluid of large follicle inhibited the COC expansion. 3. Follicular fluid showed six major fractions at retention volumes (RVs) 1.83, 1.91, 2.15, 2.34, 2.53 and 2.74 ml after separation with Superose 12 column. Of the major fractions, fractions RV2.15, RV2.34, RV2.53 and RV2.74 inhibited both COC expansion and polar body extrusion. Especially, fractions of RV2.15 and RV2.53 significantly inhibited COC expansion, oocyte denudation and polar body extrusion. In conclusion, porcine follicular fluid contained a COC expansion inhibiting ingredient (CEI) that may be contained largely in fractions RV2.15 and RV2.53. And CEI may inhibit oocyte maturation by inhibition of oocyte denudation and extrusion of the first polar body.