PROGRAMMED CELL-DEATH IN PREOVULATORY OVINE FOLLICLES

Apoptosis is a mode of physiological cell death that occurs during tis sue regression and remodeling; it is characterized by macromolecular p rotein synthesis, oligonucleosomal fragmentation, nuclear condensation , cytoplasmic shrinkage, and dissociation of cell-to-cell junctional c omplexes. Direct in situ fluorescence detection of digoxigenin end-lab eled genomic DNA was used as a marker of nuclear apoptosis within preo vulatory ovine follicles and contiguous ovarian tissues. As ovulation approached, there was a progressive increase in apoptotic cells within the ovarian surface epithelium,tunica albuginea, and apical follicula r wall, At the avascular site of rupture, follicles were devoid of ova rian surface and granulosa epithelia. Granulosa cell dispersion within the basal region of preovulatory follicles was not associated with ap optosis, Discrete physico-chemical interactions between preovulatory f ollicles and the ovarian surface are evidently a prelude to programmed cell deletion and ovulation.