The effects of prostaglandin E1 and prostaglandin E2 on in vitro myometrial contractility and uterine structure

Abstract

Objective: To estimate the effects of prostaglandin E1 (PGE1) and E2 (PGE2) on myometrial contractility and structure in vitro.

Study design: Myometrial strips from 18 women were incubated with PGE1 (10-5 mol/L), PGE2 (10-5 mol/L), or solvent (CTR) for up to 360 minutes in organ chambers for isometric tension recording. The area under the contraction curve, total collagen content, and percentage of the area covered by connective tissue were calculated at various time periods.

Results: PGE1 significantly increased in vitro myometrial contractility up to 90 minutes when compared with PGE2 and CTR (p < 0.01) and up to 180 minutes as compared with PGE2 (p < 0.05). After 360 minutes, CTR and PGE1 samples had lower total collagen content and area covered by connective tissue than PGE2 (p < 0.01).

Conclusion: The effects of prostaglandins on the uterus cannot be solely explained by contractility. Treatment with PGE1 significantly increased myometrial contractions and decreased both total collagen content and the area covered by connective tissue. Such findings may explain the higher rates of vaginal delivery, tachysystole, and uterine rupture associated with PGE1 use.

Conflict of interest statement

Disclosure: None of the authors have a conflict of interest

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Figures

Figure 1. Cumulative uterine contractility at 30, 90, 180, 360 minutes from baseline

Kruskal-Wallis One Way Analysis of Variance on Ranks followed by Dunn’s post hoc test * p

Figure 2. Total collagen concentration (mcg/g dry tissue) in samples removed at 30 or 360 minutes

Two Way Analysis of Variance on Ranks followed by Holm-Sidak post hoc test. 30 min vs 360 min p

Figure 3. Representative histology from myometrial samples treated with PGE1 and PGE2, as well as CTR collected at 30 and 360 min and stained with Masson Trichrome

After generating a digital image, the area covered by connective tissue (stained in blue) was measured as percent of the total section area; muscle fibers were stained red. Original magnification: 20X

Figure 4. Percentage area covered by connective tissue in samples removed at 30 or 360 minutes

Two Way Analysis of Variance on Ranks followed by Holm-Sidak post hoc test. a: PGE2 vs PGE1 and CTR at 360 min p