Objective: To investigate the effect of cinnamaldehyde (CIN) on the inflammation and apoptosis on human umbilical vein endothelial cells (HUVECs) induced by lipopolysaccharide (LPS), and to explore the potential mechanisms. Methods: HUVECs were divided in to 8 groups: blank control group, LPS group, LPS+(low, medium, high) dose CIN groups and (low, medium, high) CIN groups. Cell cytotoxicity was determined by trypan blue staining, mRNA expression of the inflammatory factors was determined by RT-PCR,apoptosis was determined by TUNEL staining,the signal pathway was determined by Western blot. Results: (1) Cell viability:compared with the control group,cell survival rate was significantly lower in the LPS group (P<0.01), while the survival rates were all significantly higher in the 3 LPS+CIN groups than in the LPS group (all P<0.01) in a concentration-dependent manner. (2) The mRNA expression of the inflammation factors: compared with the control group, mRNA expression of the inflammation factors were all increased in the LPS group (all P<0.01),while the effect of LPS could be significantly reversed by cotreatment with CIN in a concentration-dependent manner (all P<0.01). Compared with control group, the mRNA expression of the inflammation factors in the LPS group were all enhanced in a time-dependent manner (0,6,12,24 h),which could be significantly downregulated by cotreatment with LPS+CIN (high dose) in a time-dependent manner. (3) Cell apoptosis: compared with the control group, the apoptosis rate was significantly higher in the LPS group (P<0.01), while this effect could be significantly reversed by the cotreatment with CIN (high dose) (P<0.01). (4) Signaling pathway: compared with the control group, the phosphorylation of iκBα, p65 in HUVECs treated with LPS were rapidly up-regulated compared with their corresponding total proteins and the expression of TLR4 (all P<0.01), while the degree of p-iκBα/iκBα, p-p65/p65 and TLR4 could be significantly suppressed by cotreatment with CIN (high dose) (all P<0.01). Conclusion: CIN can attenuate LPS induced inflammation and apoptosis in HUVECs, possibly by inhibiting the activation of NF-κB signaling pathway.
目的： 观察桂皮醛对脂多糖（LPS）诱导的人脐静脉内皮细胞（HUVEC）炎症反应及凋亡的影响，并探讨其可能机制。 方法： 取培养的第3~5代HUVEC用于实验。实验共分8组，即空白对照组、LPS组（LPS 1 μg/ml干预细胞）、LPS+低剂量桂皮醛组（0.1 μmol/L桂皮醛预处理HUVEC 40 min后，再与LPS 1 μg/ml共同干预细胞）、LPS+中剂量桂皮醛组（1 μmol/L桂皮醛预处理HUVEC 40 min后，再与LPS 1 μg/ml共同干预细胞）、LPS+高剂量桂皮醛组（10 μmol/L桂皮醛预处理HUVEC 40 min后，再与LPS 1 μg/ml共同干预细胞）、低剂量桂皮醛组（0.1 μmol/L桂皮醛干预HUVEC）、中剂量桂皮醛（1 μmol/L桂皮醛干预HUVEC）和高剂量桂皮醛组（10 μmol/L桂皮醛干预HUVEC）。采用锥虫蓝染色法检测细胞活性，荧光实时定量逆转录聚合酶链反应检测细胞中炎性因子的mRNA表达水平，Western blot法检测细胞中炎性因子和信号通路相关蛋白表达及其磷酸化水平（磷酸化蛋白/总蛋白），酶联免疫吸附试验检测细胞上清液中炎性因子的浓度，TUNEL染色法检测细胞凋亡率。 结果： （1）各组细胞活性：低、中和高剂量桂皮醛组HUVEC活性与空白对照组比较差异均无统计学意义（P均>0.05）。LPS组HUVEC活性明显低于空白对照组，而LPS+低、中、高剂量桂皮醛组HUVEC活性则均明显高于LPS组（P均<0.01），且具有一定的浓度依赖性。（2）各组细胞炎性因子mRNA和蛋白表达以及上清液中浓度：干预24 h后，LPS组HUVEC中白细胞介素（IL）-1β、IL-6和肿瘤坏死因子α（TNF-α）mRNA表达水平均明显高于空白对照组（P均<0.01）；LPS+低、中、高剂量桂皮醛组HUVEC中IL-1β、IL-6和TNF-α mRNA表达水平则均明显低于LPS组（P均<0.01），且具有一定的浓度依赖性。干预0、6、12、24 h LPS组HUVEC中IL-1β、IL-6和TNF-α mRNA表达水平均明显高于空白对照组（P均<0.01），且具有一定的时间依赖性，LPS+高剂量桂皮醛组则均明显低于LPS组（P均<0.01）。干预24 h后，LPS组HUVEC中IL-1β、IL-6和TNF-α的蛋白表达及上清液中的浓度均明显高于空白对照组（P均<0.01），而LPS+高剂量桂皮醛组则均明显低于LPS组（P均<0.01）。（3）各组细胞凋亡率：LPS组HUVEC的凋亡率明显高于空白对照组（P<0.01），而LPS+高剂量桂皮醛组HUVEC的凋亡率则明显低于LPS组（P<0.01）。高剂量桂皮醛组HUVEC的凋亡率与空白对照组比较差异无统计学意义。（4）各组细胞信号通路相关蛋白表达及其磷酸化水平：LPS组HUVEC中p-iκBα/iκBα、p-p65/p65和Toll样受体4（TLR4）的蛋白表达水平均明显高于空白对照组（P均<0.01），而LPS+高剂量桂皮醛组中p-iκBα/iκBα、p-p65/p65和TLR4表达水平则均明显低于LPS组（P均<0.01）。高剂量桂皮醛组上述蛋白的表达水平与空白对照组比较差异均无统计学意义（P均>0.05）。 结论： 桂皮醛可改善LPS诱导的HUVEC的炎症反应与凋亡，机制可能与抑制核因子κB信号通路的活化有关。.
Keywords: Apoptosis; Atherosclerosis; Cinnamaldehyde; Human umbilical vein endothelial cells; Inflammation.