胎盘和子宫平滑肌组织中尿皮质素mRNA表达水平变化及其与分娩发动的关系

Level of urocortin mRNA during labor and eff ect of urocortin on myometrial contractility in vitro

目的探讨胎盘和子宫平滑肌组织中尿皮质素(urocortin,UCN)对子宫平滑肌收缩功能的影响,及UCN mRNA表达变化在分娩发动、进展中的作用。方法(1)采用半定量RT-PCR技术检测10例未临产妇女(未临产组)及20例临产妇女(临产组,其中10例潜伏期、10例活跃期)的胎盘组织和子宫平滑肌组织中UCN mRNA表达水平;(2)另取24例剖宫产术分娩产妇的子宫平滑肌组织(实验样本)行离体收缩实验,观察不同剂量UCN对子宫平滑肌的收缩作用,以及对由前列腺素F2α(PGF2α)、缩宫素诱发的子宫平滑肌收缩活动的影响,以收缩曲线下面积表示。结果(1)临产组胎盘组织中UCNmRNA的表达水平为1·23±0·52,高于未临产组的0·83±0·38,两组比较,差异有统计学意义(P<0·05);临产组子宫平滑肌组织中UCN mRNA的表达水平为1·32±0·22,高于未临产组的0·94±0·13,两组比较,差异有统计学意义(P<0·05)。临产组活跃期产妇的胎盘组织及子宫平滑肌组织中UCN mRNA表达水平明显高于潜伏期产妇,两者分别比较,差异有统计学意义(P<0·05)。(2)实验样本对不同剂量UCN均无反应,收缩曲线下面积无变化;但在加入UCN的基础上再加入PGF2α,可引起子宫平滑肌收缩曲线下面积由(2·12±0·15)cm2增加到(3·90±0·33)cm2,两者比较,差异有统计学意义(P<0·05);但UCN对缩宫素引起的子宫平滑肌收缩曲线下面积无影响。结论UCN本身对子宫平滑肌收缩功能无影响,但可以增加PGF2α及缩宫素对子宫平滑肌的收缩作用,从而参与分娩的发动和维持。

Objective To examine the expression of urocortin mRNA during labor and the effect of urocortin on myometrial contractility, arid to investigate its role in the onset and progress of labor. Methods （1） Semi-quantitative reverse transcription-polymerase chain reaction （RT-PCR）, using [3-actin as internal standard was applied to determine the levels of urocortin mRNA in human placenta and myometrium from the group of cesarean section before （ 10 cases） and during （ 10 cases in latent phase and 10 cases in active phase） labor. （2） The isolated myometrial strips of pregnant women （n=24） were prepared. The effects of urocortin with or without prostaglandin F2n（ PGF2a ） and oxytocin on myometrial contractility were evaluated by areas under the curve. Results （ 1 ） Semi-quantitative RT-PCR showed that the expression level of urocortin mRNA in placenta and myometrium after the onset of labor were higher than before labor （ 1.23±0. 52, 1.32±0. 22; 0. 83±0. 38, 0. 94±0. 13, respectively, P 〈0. 05 ）; （2） Urocortin itself did not affect myometrial tension development at all concentrations tested, but it markedly increased PGF2a-indueed myometrial contractility. The average area under the curve of controls was （2. 12±0. 15 ） cm^2 and of study strips was （3.90± 0. 33） cm^2（p 〈 0.05）; urocortin did not increase the myometrial response to oxytocin compared with controls （P 〉 0. 05 ）. Conclusion The study indicates urocortin may indirectly modulate myometrial contractility during labor.