脂多糖通过TREK-1参与妊娠子宫收缩调控的机制研究

Research on the mechanism of lipopolysaccharide involvement in regulating uterine contraction during pregnancy through TREK-1

目的分别从组织和细胞水平探究脂多糖(LPS)对妊娠子宫平滑肌收缩调控的分子机制。方法将孕16 d的C57BL/6J小鼠随机分为对照组和LPS组,LPS组小鼠腹腔注射20μg的LPS溶液建立小鼠早产模型,对照组小鼠腹腔注射等量生理盐水。采用离体子宫肌条检测组织的收缩功能改变,以及收缩关键信号分子双孔钾离子通道(TREK-1)的表达及功能变化。采用原代培养的妊娠小鼠子宫平滑肌细胞,检测LPS调控下细胞TREK-1的表达变化。结果LPS作用下,小鼠子宫组织收缩力显著增强,收缩关键信号TREK-1蛋白表达显著降低,激活TREK-1可以使LPS组小鼠子宫组织增强的收缩力出现显著下调。然而,LPS作用于妊娠小鼠原代子宫平滑肌细胞时,妊娠子宫平滑肌中高表达的TREK-1蛋白表达并没有出现显著差异。结论妊娠小鼠子宫组织在LPS作用下通过抑制TREK-1表达及功能,使子宫收缩能力加强,这可能是LPS诱发早产的作用机制之一。但LPS对小鼠妊娠子宫平滑肌细胞上TREK-1的作用可能通过细胞间信号的传递实现,并不是直接作用于子宫平滑肌细胞。提示在炎症性早产的研究中不能完全以离体细胞实验代替整体动物及组织学实验。

Objective To explore the molecular mechanism of lipopolysaccharide(LPS)on the contraction of pregnant uterine smooth muscle at tissue and cellular levels.Methods C57BL/6J mice at 16 days of gestation were randomly divided into control group and LPS group.The mice in LPS group were intraperitoneally injected with 20μg in LPS solution to establish the model of preterm birth,and the mice in control group were intraperitoneally injected with the same amount of normal saline.Isolated uterine muscle strips were used to detect changes in the contractile function of the tissue,as well as changes in the expression and function of the contraction key signaling molecule TWIK-related K+channel 1(TREK-1).Primary cultured pregnant mouse uterine smooth muscle cells were used to detect the expression of TREK-1 under the regulation of LPS.Results The contractility of mouse uterine tissues was significantly enhanced by LPS,and the protein expression of TREK-1,a key signal for contraction,was significantly reduced,and activation of TREK-1 resulted in a significant down-regulation of the enhanced contractility of mouse uterine tissues in the LPS group.However,there was no significant difference in the expression of TREK-1 protein,which was highly expressed in the smooth muscle of pregnant mice,when LPS acted on the primary uterine smooth muscle cells of pregnant mice.Conclusion Uterine contractility is enhanced in pregnant mice uterine tissues by inhibiting TREK-1 expression and function in response to LPS,and it may be one of the mechanisms by which LPS induces preterm labor.However,the effect of LPS on TREK-1 on mouse pregnant uterine smooth muscle cells may be realized through intercellular signaling and not directly on uterine smooth muscle cells.This further suggests that the animal and histological experiments cannot be completely replaced by isolated cell experiments in the study of inflammatory preterm labor.