高胆固醇血症大鼠主动脉内皮细胞NF-κB的激活和血小板源生长因子B链的表达

Detection of NF-κB activation and platelet-derived growth factor-B expression in endothelial cells of hypercholesterolemic rats

目的 验证体外培养的内皮细胞经轻微修饰低密度脂蛋白 (mm LDL)刺激后激活细胞核因子κB(NF κB)的现象可否同样在高胆固醇血症大鼠主动脉内皮细胞内出现并促进血小板源生长因子B链 (PDGF B)的表达 ,以及年龄对NF κB PDGF B信号传导通路的影响。方法 胃饲高胆固醇乳剂建立高胆固醇血症大鼠模型 ,免疫组织化学染色法 [链霉素抗生物素蛋白 过氧化物酶 (SP)法 ]明确主动脉内皮细胞NF κB激活后发生核转位的情况 ;应用原位杂交技术观察内皮细胞PDGF BmRNA的表达 ,同时应用免疫组织化学染色法 (SP法 )观察内皮细胞合成PDGF B链的情况。结果 与对照组相比 ,胃饲高胆固醇乳剂 6周后 ,2个月龄大鼠出现高胆固醇血症 ,主动脉内皮细胞NF κB核转位的比例明显增加 ,PDGF BmRNA的表达也增多。 10个月龄对照组Wistar大鼠的主动脉内皮细胞几乎不表达PDGF BmRNA ,摄入高胆固醇乳剂 16周后 ,内皮细胞表达PDGF BmRNA明显增多。较之摄入胆固醇同时期的 2个月龄大鼠 ,NF κB的核转位及内皮细胞PDGF B链的合成均增多(0 4 6 1± 0 0 75比 0 35 0± 0 0 94 ;0 2 30± 0 0 4 0比 0 185± 0 0 37) ,其差异有显著性意义 (P <0 0 5 ;P <0 0 0 1)。结论 高胆固醇血症能激活大鼠主动脉内皮细胞的NF κB 。

Objective To detect whether the activation of nuclear factor-kappa B (NF-κB) in endothelial cells induced by mm-LDL can promote platelet-derived growth factor-B(PDGF-B) expression in vitro, and whether it is also present in hypercholesterolemic rats in vivo, influence of age on NF-κB and PDGF-B signal tranduction pathway. Methods Established hypercholesterolemic rat model by feeding with a high-cholesterol ration. The activation of NF-κB in aortic endothelial cells was identified by immunohistochemical staining, the expression of PDGF-B mRNA and PDGF-B protein were examined using in situ hybridization and immunohistochemistry respectively. Results In comparison with the control rats, a positive immunostaining of NF-κB in nuclei of aortic endothelial cells of the experimental rats was detected after a high cholesterol ration for 6 weeks. The number of endothelial cells expressing PDGF-B mRNA increased and the intensity was dependent upon the duration of high-cholesterol intake. NF-κB translocation (0.461 ± 0.075 vs. 0.350±0.094, P<0.05) and PDGF-B expression in 10-month old Wistar rats were more remarkable than that of 2-month old rats after having cholesterol for 16 weeks. Immunohistochemical staining for PDGF-B gave a similar result (0.230±0.040 vs. 0.185±0.037, P<0.001). Conclusions Hypercholesterolemia is capable of activating nuclear translocation of NF-κB and promoting expression of PDGF-B in rat aortic endothelial cells in vivo, this coincided with the results obtained in ox-LDL or mm-LDL experiments on endothelial cells in vitro. This phenomenon is much more evident in 10-month old rats which indicates that age might have a close relationship with NF-κB - PDGF-B signal transduction pathway.