Opposite regulation of clusterin and LH receptor in the swine corpus luteum during luteolysis

Abstract

-Luteolysis, which occurs in a cyclical way to remove luteal tissue, may be an example of physiological apoptosis which counterbalances rapid tissue growth after ovulation. Clusterin is a multifunctional glycoprotein expressed in different tissues undergoing apoptosis. In this study we investigated clusterin and LH receptor gene expression during luteolysis as potential regulators of tissue growth and regression. Luteolysis was induced in pregnant sows (45 days) by Cloprostenol (PGF 2α analogue) treatment. Clusterin expression increased in the corpora lutea of pregnant sows ovariectomized 0, 6, 12, 24, 48 or 72 (n = 3) h after the luteolytic stimulus; maximum values were observed 24-48 h after the treatment (P < 0.01). An opposite trend between clusterin mRNA expression and markers of luteal function, such as progesterone levels in the corpora lutea and plasma, and LHr mRNA expression levels, was observed; moreover, clusterin expression was positively correlated with the degree of genomic DNA fragmentation, a marker of occurring apoptosis (P < 0.01). This pattern may be important in regulating luteolysis by a switch between luteotrophic and apoptotic stimulus. Our data indicate that P4 levels decrease prior to the increase in clusterin mRNA and the drop in LHr mRNA expression; we may therefore hypothesize a split between functional and structural luteolysis as reported in other species.LH receptor / tissue growth / clusterin / apoptosis / luteolysis

Matrix Metalloproteinases -2 and -9 in Swine Luteal Tissue Angiogenesis and Angioregression

“…The angiogenic process should be rigorously regulated to allow repeated opportunities for fertilization. After a first period of rapid growth the tissue develops a stable organisation and prepares to switch to the phenotype required for its next apoptotic regression (Bacci et al, 1996;Forni et al, 2003). During the process of vascular invasion and apoptosis process, the activation of matrix metalloproteinases (MMPs) is required to permit the remodelling of extracellular matrix (ECM) (Pitzel et al, 2000).…”

Pre-translational regulation of luteinizing hormone receptor in follicular somatic cells of cattle

“…This is consistent with a negative feedback mechanism, for up-regulating LHR, being active in these cells to counteract a loss of LH-dependant events. It is tempting to speculate that there could also be a link with the steroidogenic pathway as decreasing amounts of LHR mRNA have been reported to follow parallel decreases in luteal and circulating concentrations of progesterone ( Forni et al, 2003 ). The fact that removal of FSH from the GC media led to a >5-fold reduction in amounts of LHR mRNA suggests a direct regulatory relationship between FSH and LHR mRNA in GC and studies in rats indicate protein kinase B is an essential component of FSH-mediated GC differentiation ( Zeleznik et al, 2003 ).…”

Porcine circovirus type 2 detection in in vitro produced porcine blastocysts after virus sperm exposure

“…Amplification of ß‐actin gene was performed for all sample as internal control as previously described (Forni et al ).…”