Unilaminar follicular cells transiently express galectin-3 during ovarian folliculogenesis in pigs

- Galectin-3 is expressed in some ovarian follicles and corpus luteum of pigs.
- Galectin-3 is immunostained in unilaminar, but not in multilaminar, follicular cells.
- Galectin-3 is immune-localized in granulosa cells in atretic follicles.
- Galectin-3 is immunostained in luteal cells in corpus luteum of pigs.
- Galectic-3 plays a role in either early folliculogenesis or regression of ovarian follicles, or both.

The localization of galectin-3, a β-galactoside-binding animal lectin, was immunohistochemically studied in the ovaries of pigs to determine its expression in ovarian folliculogenesis. Various stages of ovarian follicles were identified in the ovaries of adult pigs. Galectin-3 was immunostained in the squamous follicular cells surrounding oocytes in primordial follicles and in the unilaminar granulosa cells of primary follicles, but not in oocytes of multilaminar follicles (including primary, secondary, and tertiary Graafian follicles). As in adult ovaries, galectin-3 immunoreactivity was prominent in the unilaminar follicles in neonatal ovaries. Galectin-3 was also immunolocalized in the luteal cells in the corpus luteum and granulosa cells of atretic follicles as well as in interstitial macrophages in porcine ovaries. Collectively, these results suggest that galectin-3 is transiently expressed in follicular cells in the unilaminar ovarian follicles (primordial and primary) but not in multilaminar ovarian follicles (primary to tertiary), implying that galectin-3 is embryologically involved in ovum generation.