Expression of hydrogen sulfide, hydrogen-sulfide synthase and cyclooxygenase-2, and their mechanisms of action in amniotic tissues

Abstract

Purpose: To investigate the expressions of cystathionine β-synthase (CBS), cystathionine γ - lyase (CSE) and cyclooxygenase - 2 (COX - 2) and their relationships with premature delivery in amniotic tissues.
Methods: Parturients were divided into three groups: 40 preterm-labor parturients (PTL group), 28 term-labor parturients (TL group), and 28 term non-labor parturients (TNL group). Changes in expressions of CBS, CSE and COX-2 were determined by Western blot (WB) in amniotic tissues of parturients in the three groups. The expression of COX - 2 was determined after the amniotic tissues of parturients in the TNL group were cultured in vitro and processed by exogenous hydrogen-sulfide (H₂S).
Results: The expression level of COX - 2 was significantly lower in the TNL group, when compared with the PTL and TL groups (p < 0.05). The  expression of CBS was increased in the order PTL > TL > TNL, with TNL group having the highest level, and there were significant differences in CBS expressions among the three groups (p < 0.05).
Conclusion: These results suggest that when the expressions of CBS and CSE are down-regulated, the decreased H₂S synthesis promotes the overexpression of COX - 2 by NF - kB signaling pathway, causing increased prostaglandin synthesis which results in premature delivery.

Keywords: Cystathionine β - synthase, Cystathionine γ - lyase,  Cyclooxygenase - 2; Amniotic tissues; Preterm labor