The Effect of Imbalanced Progesterone Receptor-A/-B Ratio on Gelatinase Expressions in Endometriosis

Objective Objective: Gelatinases degrade extracellular matrix (ECM) components to make physiological remodeling and contribute to pathological tissue destruction in endometriosis. It is known that gelatinases’ function is resistant to suppression by progesterone in endometriosis. The ability of progesterone to impact gene expression depends on the progesterone receptor-A/-B (PR-A/PR-B) ratio. An imbalanced PR-A/PR-B ratio in endometriotic tissue may be the result of differential expressions of MMP-2 and MMP-9, which could be important in etiology and pathogenesis of disease. MaterialsAndMethods Methods: This study enrolled 40 women, 20 in the case group who were diagnosed with stages III/IV endometriosis and 20 normal subjects without endometriosis (controls) who referred to Royan Institute, Tehran, Iran in 2013-2014. We obtained 60 tissue samples [ectopic (n=20), eutopic (n=20), and normal endometrium (n=20)]. RNA was extracted from tissue samples for analyses of PR-A, PR-B, MMP-2, and MMP-9 mRNA expressions by real-time PCR. Results Result(s): There was significantly lower expression of the PR-B isoform in ectopic tissues compared to the control (P=0.002) and eutopic endometrium (P=0.006) tissues. PR-A expression was higher, but not significant, in the same ectopic and eutopic endometrium tissues compared to the control tissues (P>0.05). There was significant overexpression of MMP-9 in ectopic samples compared to control (P=0.014) and eutopic endometrium (P=0.012) samples. The PR-A/PR-B ratio was not significantly higher in both eutopic and ectopic samples compared to the control samples (P>0.05). Conclusion Conclusion(s): Our findings support an altered PR-B expression in endometriosis, which may be associated with MMP-9 overexpression. This finding can be important for disease pathogenesis.