| Preterm delivery is the main cause of morbility and death of neonate in most of the countries.The pre-excitement of uterine smooth muscle will possiblly lead to preterm labor. Intracellular free calcium ions is the key point in smooth muscle's excitation-contraction coupling.And how to make the uterus back to quiescence condition is the key problem in preterm labor research.Regulation of myometrial functions during gestation,labor and birth are in the forefront of research in reproductive sciences.The complexity of the problem is reflected by our scant understanding of the intimate cellular and molecular events underlying these phenomena,despite extensive efforts spanning several decades.Unlike other smooth muscles,the myometrium is,to a large extent,under hormonal control.Of these, progesterone is a major factor maintaining uterine quiescence throughout pregnancy. Unlike most other species,labor and delivery in humans occur without a decrease in maternal,fetal and amniotic fluid progesterone levels.Although the theory of "functional progesterone withdrawal'may explain this special phenomenon well,but the mechanism is still controversy.In few years,the study of the mechanism of progesterone has focus on the classic genomic and fast non-genomic mechanisms.Of these,the non-genomic mechanism has become hot spot for its fast and derect features.But the experiments in and out of our country are limited in animal test,and the several tests on people ex vivo have different resule jet.We may have a known on the mechanism of the initiate of human parturition and prematurity through the study of progesterone on human pregnant myometrium,and provide theoretical evidence for preventing and treating prematurity and other deseases owing to abnormally myometrium contractile activity.In this article,we hope to take a study of regulation of progesterone on human pregnant myometrium contractile activity by determination of isometric tension of human myometrial tissue and then we hope to realize the possible mechanism of progesterone's this effect to uterine contractility by observing its effect on intracellular free calcium ions of human myometrial cells.Thus we can possiblly get a message of the effect of progesterone on human pregnancy and labor.Methods:1.Determinate the isometric tension of human myometrial tissue:using progesterone or the composition of progesterone and the antagonist of its acceptor(RU486) directly into the myometrial tissue bath which had already set up regular myometrium contractile,we observe the state of myometrium contractile.we use the myometrial cells of TNL and TL to do experiments as follow:Myometrium contractile induced and not induced by OT.2.Isolation and culture of human myometrial cells:All biopsies were taken from the lower isthmic part of uteri.After co-digestion with collagenase I and DNAase I,they were cultured in 10%FCS DMEM.We divide them into two groups of TNL and TL.3.Measurement of changes of intracellular free calcium with confocal microscopy: Using the first passage myometrial cells as the target cells,we divide the cells into three groups and do experiments as follow:(1)The experiment of progesterone concentration effect;(2)The experiment of progesterone time course effect;(3)The experiment of RU486.We analysed the changes of intracellular free calcium ions before/after the addition of different types agents.Results:1.Results of determination of isometric tension of human myometrial tissue:The depression effece of progesterone on myometrial tissue contractile are not signigficant in the two group without OT.In myometrium contractile induced by OT group, the depression effece of progesterone shows an concentration dependence(P＜0.05).The effect is stronger in TNL group then TL group(P＜0.05).It has no difference between every group if we add progesterone and RU486 simultaneously(P＞0.05).2.Results of cell culture:Vigorous SMCs were acquired more efficiently by using the collagenase with DNase at the same time.Others had shown that the purity of primary passage SMCs was nearly 100%.3.Results of confocal microscopy:All of the concentration(10-8 mol/L,10-7 mol/L,10-6 mol/L) of progesterone can depress intracellular free calcium ions(P＜0.01);All of the time course can depress intracellular free calcium ions(P＜0.01),This effect of progesterone can be antagonisted by RU486,the antagon of it's receptor(P＜0.01).The RU486 itself has no effect of this(P＞0.05).Conclusion:1.Progesterone has a depress effect on human pregnant myometrium contractile but it has differences between contractile without OT and OT induce contractile groups.This effect shows a pose dependency and it can be antagonisted by RU486. 2.The effect of progesterone on depress the increase of Intracellular free calcium ions induced by oxitocin are significant and it can be antagonist by RU486 and the RU486 alone has no effect like that.The time dependence of this depress effect are significant in people term pregnant myometrial cells.It can be antagonisted by RU486.Above all,progesterone can depress human pregnant myometrium contraction via the fast non-genome mechanism and it shows a pose and time dependence.The effect are different between TNL and TL group.
|
PDF Full Text Request