过氧化物酶体增殖物激活受体γ及其配体对早孕期绒毛组织及细胞滋养细胞浸润能力的影响

目的探讨过氧化物酶体增殖物激活受体γ（PPARγ）及其配体对早孕期绒毛组织及细胞滋养细胞浸润能力的影响。方法采用免疫组化方法、免疫荧光细胞化学染色法、蛋白印迹法和RT-PCR技术检测20例孕6～8周（早孕早期组）及20例孕11～12周（早孕晚期组）绒毛组织及细胞滋养细胞中的PPARγ蛋白及其mRNA的表达;并检测不同浓度PPARγ激动配体——15-脱氧-前列腺素J2（15-d-PGJ2）和曲格列酮,以及不同浓度拮抗配体——双酚丙烷二环氧甘油醚（BADGE）对原代无血清培养的细胞滋养细胞浸润能力的影响。结果（1）PPARγ／蛋白在早孕早期组和早孕晚期组绒毛组织中均有表达,主要定位在细胞滋养细胞核中,合体滋养细胞及绒毛间质细胞中无表达。（2）早孕早期组绒毛组织和培养的细胞滋养细胞中,PPARγ／蛋白表达水平分别为1．35±0．08、1．13±0．11,PPARγ／mRNA表达水平分别为36．0±5．1、13．4±3．1;早孕晚期组绒毛组织和培养的细胞滋养细胞中,PPARγ／蛋白表达水平分别为1．17±0．03、0．86±0．05,PPARγ mRNA表达水平分别为23．3±5．5、6．1±1．3,早孕晚期组PPARγ蛋白及其mRNA表达水平明显低于早孕早期组,两组分别比较,差异均有统计学意义（P〈0．05）。（3）PPARγ／激动配体15-d-PGJ2和曲格列酮均有抑制细胞滋养细胞的浸润的作用。15-d-PGJ2浓度为1、10μmol／L,曲格列酮浓度为10μmol／L时,早孕早期组细胞滋养细胞浸润指数分别为0．57±0．03、0．43±0．02、0．50±0．06,早孕晚期组分别为0．69±0．02、0．59±0．03、0．66±0．05,两组分别比较,差异均有统计学意义（P〈0．05）。（4）PPARγ拮抗配体BADGE浓度为20、50μmol／L时,早孕早期组细胞滋养细胞浸润指数分别为1．23±0．07和1．58±0．04;早孕晚期组分别为1．05±0．03和1．38±0．08,两组分别比较,差异均有统计学意义（P〈0．05）。结论PPARγ／在调节滋养细胞浸润过程中起重要作用;在早孕期胎盘绒毛组织,PPARγ／激动配体可抑制滋养细胞浸润;PPARγ／拮抗配体可促进滋养细胞浸润,且能部分逆转激动配体的作用。

Effect of peroxisome proliferators-activated receptor gamma ligands on cytotrophoblast invasion in first trimester pregnancy

OBJECTIVE: To investigate the expression of peroxisome proliferators-activated receptor gamma (PPARgamma) in trophoblast and relation between PPARgamma ligands and trophoblast invasion. METHODS: We examined the expression of PPARgamma by immunohistochemistry, immunocytochemistry and real time quantitative PCR. We next examined, using the cytotrophoblast culture model, the biological role of PPARgamma ligands in vitro. RESULTS: PPARgamma was mainly localized in the nuclei of villous cytotrophoblast and extravillous cytotrophoblast of cell islands and cell columns. In villous tissue and cultured trophoblast from early first trimester, the level of expression of PPARgamma mRNA and protein was 36.0 +/- 5.1, 13.4 +/- 3.1 and 1.35 +/- 0.08, 1.13 +/- 0.11; from late first trimester it was 23.3 +/- 5.5, 6.1 +/- 1.3 and 1.17 +/- 0.03, 0.86 +/- 0.05, and the expression of PPARgamma was obviously decreased (P < 0.05). Our studies showed that both natural and synthetic PPARgamma agonists inhibited cytotrophoblast invasion in a concentration-dependent manner. In trophoblast from early and late first trimester, while 15-d-PGJ(2) at concentrations 1 and 10 micromol/L, troglitazone at a concentration 10 micromol/L, invasion index was 0.57 +/- 0.03, 0.43 +/- 0.02, 0.50 +/- 0.06 and 0.69 +/- 0.02, 0.59 +/- 0.03, 0.66 +/- 0.05. The effect on inhibition of trophoblast was significant compared with control (P < 0.05). Conversely, PPARgamma antagonists promoted cytotrophoblast invasion. Furthermore the PPARgamma antagonist abolished inhibitory effect of the PPARgamma agonists partially. PPARgamma ligands had a significant effect on cytotrophoblast from early first trimester more than cytotrophoblast from late first trimester (P < 0.05). CONCLUSIONS: PPARgamma plays an important role in the modulation of trophoblast invasion. Consequently, one can hypothesize that abnormal increases in the production of PPARgamma agonist ligands in placenta can alter trophoblast invasion and generate human pregnancy diseases such as preeclampsia.