Potential Regulators of Physiological Cell Death in the Corpus Luteum

Follicular dynamics and gene expression in granulosa cells, corpora lutea and oocytes from gilts of breeds with low and high ovulation rates

“…This indicates a possible occurrence of an increased ratio of apoptosis in the CL of commercial line compared with Piau sows. Similar higher expression of BAX mRNA in the regressing CL was reported during luteolysis in cattle and humans (Rueda et al 1997;Sugino et al 2000;Pretheeban et al 2010). Although in the present study the expression of BCL2 mRNA was similar between breeds on Day 10, previous studies in humans demonstrated higher expression of BCL2 mRNA in the mid-luteal phase CL (Sugino et al 2000).…”

“…Therefore, it can be suggested that the follicle in the Piau breed provides a different environment for follicle apoptosis than that in commercial line follicles, which may contribute to the lower prolificacy of the Piau breed. Many reports have shown that apoptosis occurs during luteolysis and it has also been established that apoptosis plays a role in CL regression at the end of the oestrous cycle (Rueda et al 1997). In the present study the amount of transcript that encodes the membrane protein Fas in the CL was similar between breeds, whereas expression of FASL mRNA was higher in Piau CL, which may result in a more effective apoptosis signalling towards luteolysis in this breed.…”

“…The findings of the present study indicate that BCL2 mRNA abundance in the CL did not differ between breeds during the oestrous cycle. However, the mRNA abundance of the pro-apoptotic factor BAX was higher in commercial line gilts on Days 4 and 18, resulting in a higher ratio of BAX : BCL2 mRNA compared with that in the Piau breed, a change consistent with bax-mediated apoptosis (Rueda et al 1997). This indicates a possible occurrence of an increased ratio of apoptosis in the CL of commercial line compared with Piau sows.…”

“…In the present study, mRNA expression of candidate genes involved in apoptotic pathways in GC and luteal cells differed between breeds during the oestrous cycle. The FasFasL system has been reported in many species as the major mechanisms regulating GC (Matsuda-Minehata et al 2008) and luteal cell (Juengel et al 1993;Rueda et al 1997;Sakamaki et al 1997) apoptosis. In the present study, FAS mRNA was more abundant in GC from healthy than atretic follicles during the oestrous cycle, consistent with previous findings in several species (Porter et al 2001;Dharma et al 2003;Inoue et al 2006).…”

“…Several genes belonging to the bcl2 family, including both anti-and pro-apoptotic family members, are known to be expressed in luteal cells of various species (Rodger et al 1995;Rueda et al 1997;Goodman et al 1998). The Bcl2 : Bax expression ratio within a cell is related to its potential to become apoptotic, and it has been proposed that Bax homodimers promote cell death, whereas Bcl2 homodimers function as repressors of cell death (Oltval et al 1993).…”