滋养细胞内质网应激特征性分子葡萄糖调节蛋白及内质网凋亡因子caspase-12与子痫前期发病的关系

Effect of endoplasmic reticulum stress-responsive protein glucose-regulated protein 78, 94 and endoplasmic reticulum apoptosis factor caspase-12 in trophocyte on the pathogenesis of preeclampsia

目的 探讨滋养细胞内质网超微结构变化及内质网应激特征性分子--内质网分子伴侣葡萄糖调节蛋白（GRP）78、94和内质网凋亡因子--半胱氨酸天冬氨酸蛋白酶12（caspase-12）mRNA及蛋白表达与子痫前期发病的关系.方法 选择2008年7月-2010年1月在南京医科大学第一附属医院分娩的孕妇共65例,其中子痫前期孕妇30例（子痫前期组）,健康孕妇35例为对照组.应用透射电镜扫描观察胎盘组织中滋养细胞内质网超微结构改变,逆转录（RT）PCR技术检测胎盘组织中GRP78、GRP94和caspase-12 mRNA的表达,蛋白印迹法检测胎盘组织中GRP78、GRP94和caspase-12蛋白的表达.结果 （1）对照组胎盘组织中滋养细胞内质网体积无明显增大,内质网无扩张也无肿胀变化;子痫前期组滋养细胞内质网水肿,数量减少,内质网体积增大,内质网扩张及液泡化,且内质网脱颗粒改变明显.（2）子痫前期组胎盘组织中GRP78 mRNA及蛋白表达水平分别为2.59±0.09及0.81±0.31,显著高于对照组的1.16±0.07及0.40±0.10,两组分别比较,差异均有统计学意义（P〈0.01）.（3）子痫前期组胎盘组织中GRP94 mRNA和蛋白表达水平分别为1.31±0.91及0.55±0.24,显著高于对照组的0.63±0.57及0.22±0.09,两组分别比较,差异均有统计学意义（P〈0.01）.（4）子痫前期组胎盘组织中caspase-12 mRNA和蛋白表达水平分别为4.03±0.65及1.56±0.17,显著高于对照组的1.85±0.85及0.91±0.69,两组分别比较,差异均有统计学意义（P〈0.01）.结论 子痫前期孕妇的滋养细胞内质网有明显的扩张及肿胀性改变;胎盘组织中GRP78、GRP94以及caspase-12 mRNA及蛋白表达水平比健康孕妇有明显升高.提示,内质网应激介导的滋养细胞凋亡可能是子痫前期发病的又一重要机制.

Objective To evaluate the relationship between pathogenesis of preeclampsia （PE） and the ultrastructure change of the endoplasmic reticulum in trophocyte, mRNA and protein expression levels of endoplasmic reticulum molecular chaperone glucose-regulated protein 78 （GRP78）, glucose-regulated protein 94 （GRP94）, endoplasmic reticulum apoptosis factor cysteine protease protein 12 （caspase-12）.Methods Sixty-five pregnant women who were hospitalized in the First Affiliated Hospital of Nanjing Medical University from July 2008 to January 2010, were selected as the subject. Thirty pregnancy women diagnosed with PE were divided into PE group and 35 normal pregnant women were used as control group.Electron Microscopy was used to measure ultrastructure change of the endoplasmic reticulum in placenta trophocyte. Reverse transcription（RT） PCR and western blot were used to investigute the expression levels of GRP78, GRP94, caspase-12 mRNA and protein in placenta. Results （1） In control group the volume of endoplasmic reticulum does not increase; no swelling and no expansion of endoplasmic reticulum was found.In PE group the edema number of endoplasmic reticulum was reduced; the volume of endoplasmic reticulum increased; expansion and vacuolation of cavity and degranulation of the endoplasmic reticulum was observed significantly. （2） The mRNA and protein expression levels of GRP78 in placenta of PE group （2.59 ± 0. 09 and 0. 81 ±0. 31） were significantly higher than those in placenta of control group （1. 16 ±0. 07 and 0. 40 ± 0. 10, P 〈0. 01）. （3） The mRNA and protein expression levels of GRP94 in placenta of PE group （1.31 ± 0. 91 and 0. 55 ±0. 24） were significantly higher than those in placenta of control group （0. 63 ±0. 57 and 0. 22 ±0. 09, P 〈 0. 01）. （4） The mRNA and protein expression levels of caspase-12 in placenta of PE group （4. 03 ± 0. 65 and 1.56 ± 0. 17） were significantly higher than those in placenta of control group （1.85 ± 0. 85 and 0. 91 ± 0. 69, P 〈 0. 01）. Conclusion The obvious expansion of endoplasmic reticulum in trophocyte and the increased expression levels of GRP78, GRP94 and caspase-12 indicate that endoplasmic reticulum stress-mediated apoptosis may be involved in the pathophysiological processes of PE.