Caspase-3-mediated apoptosis and cell proliferation in the equine endometrium during the oestrous cycle

Abstract

Cell proliferation and apoptosis are hormone-dependent physiological processes involved in endometrial growth and regression. The aims of the present study were: (1) to evaluate endometrial cell proliferation using proliferating cell nuclear antigen (PCNA) expression; (2) to evaluate the induction of endometrial cell death by the expression of active caspase-3 and the apoptotic phenotype visualised by DNA fragmentation; and (3) to relate these observations to endometrial tissue dynamics in the equine endometrium throughout the oestrous cycle. Endometria were assigned to follicular and luteal phases based on ovarian structures and plasma progesterone. Cell proliferation and active caspase-3-mediated apoptosis were expressed in both phases of the oestrous cycle. In the luteal phase, PCNA expression was higher than in the follicular phase. Highest PCNA activity was noted in the luminal and glandular structures. Active caspase-3 staining was increased in luminal epithelium and deep glandular cells during the luteal phase. However, in the follicular phase, stromal cells showed greater active caspase-3 expression. Only a few apoptotic endometrial cells were detected by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) and these cells were mostly present in luminal and glandular structures. A simultaneous increase in DNA, cell proliferation and protein synthesis was observed in the endometrium during the mid-luteal phase. This suggests that cell hyperplasia occurs at the time the histotroph is needed for eventual embryo nourishment.

The study of endometrium at gestational days 5 and 15 in dairy goats (Capra hircus)

“…The homeostasis of the endometrial tissue achieved by E2/P4-dependent processes involving endometrial growth and regression under physiological conditions in a cyclical pattern plays an important role in the preparation of the uterus for each new oestrous cycle or for supporting pregnancy (Roberto da Costa et al 2007). Several studies performed in humans and different animal species, such as horses, dogs, rats and rabbits, have shown that the cyclic pattern of ovarian secretion of E2 and P4 affects cell proliferation and apoptosis in the uterine endometrium.…”

Involution dependent changes in distribution and localization of bax, survivin, caspase‐3, and calpain‐1 in the rat endometrium

“…To date, the results of studies have shown that the expression and localization of caspase‐3 in the luminal and glandular epithelium of endometrium vary according to the cell types, mammalian species and the sexual cycle. Roberto da Costa et al () reported that in the equine endometrium during the oestrous cycle, active caspase‐3 staining is increased in luminal epithelium and deep glandular cells during the luteal phase, however, in the follicular phase, stromal cells showed greater active caspase‐3 expression. These authors also stated that only a few apoptotic endometrial cells are detected by TUNEL and these cells are mostly present in luminal and glandular structures (Roberto da Costa et al, ).…”

“…Apart from apoptosis, caspases also play a role in cellular processes such as differentiation and cell cycle (in reviewed Shynlova et al, ). Several studies have suggested that endometrial cell death is regulated by the expression of active caspase‐3 during the menstrual or estrous cycle (Otsuki, ; Roberto da Costa et al, ; Van Cruchten et al, ; Arai et al, ) and early pregnancy (Zhang and Paria, ; Oner et al, ).…”

Cytokines and neutrophil extracellular traps in the equine endometrium: friends or foes?

“…In the mare, as in other mammals, endometrium cyclic regulation is mainly driven by the changing pattern of the ovarian steroid hormones estradiol (E2) and progesterone (P4), and endometrial prostaglandins (PG) (Stout and Allen 2002;Roberto da Costa et al 2007a). Thus, also in the mare, the endometrium undergoes angiogenic changes and cellular proliferation/apoptosis to prepare the uterus for pregnancy (Ferreira-Dias et al 2001, Roberto da Costa et al 2007a;2007b, 2008. In fact, in the mid luteal phase, cell hyperplasia and increased protein synthesis occur in equine endometrium, at the time the histotroph would be needed for eventual embryo nourishment (Roberto da Costa et al 2007a).…”

“…Thus, also in the mare, the endometrium undergoes angiogenic changes and cellular proliferation/apoptosis to prepare the uterus for pregnancy (Ferreira-Dias et al 2001, Roberto da Costa et al 2007a;2007b, 2008. In fact, in the mid luteal phase, cell hyperplasia and increased protein synthesis occur in equine endometrium, at the time the histotroph would be needed for eventual embryo nourishment (Roberto da Costa et al 2007a). …”