Collagen messenger rna expression in the human amniochorion in premature rupture of membranes

Objective: It has been suggested that there is a decrease in the collagen content of the fetal membranes when there is premature rupture of the membranes before the onset of labor. This study was designed to determine whether decreased amniochorion collagen production (as measured by reduced amounts of messenger RNA) or alterations in relative production of different fibrillar and nonfibrillar collagens are associated with premature rupture of the membranes. Study Design: Fetal membranes were collected after preterm (24-36 weeks of gestation) and term (≥37 weeks of gestation) deliveries both with and without premature rupture of the membranes. Specimens with evidence of histologic chorioamnionitis were excluded. The messenger RNA levels for fibrillar collagen types I, III, and V and fibril-associated collagens with interrupted triple-helices types XII and XIV were measured with relative quantitative reverse transcriptase–polymerase chain reaction. Results: The messenger RNA levels for fibrillar collagens decreased with advancing gestational age. Preterm premature rupture of membranes was associated with increased messenger RNA levels for fibrillar collagens and fibril-associated collagens with interrupted triple-helices collagen XII, but not type XIV. The greatest change in relative amounts of collagen messsenger RNA was demonstrated by an increased type I/XIV ratio, which was due to the up-regulation of type I levels, but not type XIV levels. Conclusion: A rise in fibrillar collagen production (messenger RNA) for types I, III, and V and fibril-associated collagens with interrupted triple-helices collagen type XII is observed with preterm premature rupture of the membranes. There is no evidence for a similar up-regulation of messenger RNA for fibril-associated collagens with interrupted triple-helices collagen type XIV. The rise in the collagen I/XIV messenger RNA ratio in preterm premature rupture of the membranes may result in collagen fibrils without enough stabilizing fibril-associated collagens with interrupted triple-helices type XIV on the fibril surface to maintain structural integrity. (Am J Obstet Gynecol 2002;187:1679-85.)