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Collagenolytic effect of disintegrated bacterial cell extracts on the human amniotic membrane at term pregnancy
A Norström1, J Platz-Christensen, E Sandberg
1Department of Obstetrics and Gynaecology, Sahlgrenska University Hospital, Göteborg, Sweden.
Abstract:
Bacterial ascending from the cervix may infect the membranes and amniotic fluid, contributing to their premature rupture. In the present in vitro study, isolated amniotic membranes were exposed to different concentrations of disintegrated bacterial cells. Collagenolysis was estimated by the ratio of acid-soluble/insoluble hydroxyproline. The amniotic membrane proteins were separated by electrophoresis after incubation with 14C proline and disintegrated bacterial cells. The proportion of soluble hydroxyproline increased with the bacterial concentration used, and the radioactivity decreased in proteins of the 30- to 80-kD range. The data support the notion that bacteria contain collagenolytic enzymes affecting human amniotic membranes.
Insights
Bacteria can cause premature rupture of membranes by releasing collagenolytic enzymes. This study shows bacterial collagenases degrade human amniotic membranes, increasing soluble collagen and decreasing structural proteins.
Area of Science:
- Obstetrics and Gynecology
- Microbiology
- Biochemistry
Background:
- Bacterial infections ascending from the cervix can lead to chorioamnionitis.
- Chorioamnionitis is a significant risk factor for premature rupture of membranes (PROM).
- The specific mechanisms by which bacteria affect amniotic membranes are not fully understood.
Purpose of the Study:
- To investigate the effect of bacterial collagenolytic enzymes on human amniotic membranes in vitro.
- To determine if bacterial components can degrade collagen in the amniotic membrane.
- To explore the impact of bacterial exposure on amniotic membrane protein structure.
Main Methods:
- Isolated human amniotic membranes were incubated with varying concentrations of disintegrated bacterial cells.
- Collagenolysis was quantified by measuring the ratio of acid-soluble to acid-insoluble hydroxyproline.
- Amniotic membrane proteins were analyzed using electrophoresis after incubation with 14C proline and bacterial components.
Main Results:
- Increased bacterial concentration led to a higher proportion of soluble hydroxyproline, indicating collagen degradation.
- Radioactivity in the 30- to 80-kD protein range decreased, suggesting bacterial enzyme activity on structural proteins.
- The findings demonstrate a direct effect of bacterial components on amniotic membrane integrity.
Conclusions:
- Bacteria possess collagenolytic enzymes that can degrade human amniotic membranes.
- Bacterial collagenases contribute to the breakdown of amniotic membrane structure.
- This enzymatic activity may play a role in the pathogenesis of premature rupture of membranes.