牙龈卟啉单胞菌胞外蛋白对牛主动脉内皮细胞存活的影响

目的:探讨牙周致病菌牙龈卟啉单胞菌胞外蛋白对体外培养牛主动脉内皮细胞(BAECs)存活的影响.方法:盐析法提取牙龈卟啉单胞菌胞外蛋白;不同浓度的胞外蛋白(200、300、400、500、600μg/mL)分别作用于体外培养的BAECs 24 h,对照组为无细菌胞外蛋白作用的BAECs;另外,用400μg/mL胞外蛋白分别作用于BAECs 6、12、24、36h,对照组细胞同样培养6、12、24、36 h,比较实验组与对照组BAECs存活率的变化;采用台盼蓝染色法检测BAECs存活率.采用SPSS 10.0软件包对数据进行独立样本t检验.结果:当作用于BAECs的牙龈卟啉单胞菌胞外蛋白浓度在200～600μg/ml.范围内时,BAECs存活率均低于对照组(P<0.05),且随细菌蛋白浓度增加而降低;在36 h内,随着时间的延长,实验组和对照组的BAECs存活率均有下降,但实验组降低的幅度大于对照组(P<0.05),显示细菌胞外蛋白对BAECs存活率的影响具有时间依赖性.结论:牙龈卟啉单胞菌胞外蛋白可导致体外培养的牛主动脉内皮细胞存活率降低,并呈现剂量和时间依赖性.

The effect of extracellular protein from Porphyromonas gingivalis ATCC 33277 on viability of bovine aortic endothelial cells

PURPOSE: To evaluate the effect of extracellular protein from Porphyromonas gingivalis on the viability of bovine aortic endothelial cells (BAECs). METHODS: Extracellular protein was extracted from the culture supernatant of P. gingivalis ATCC 33277 by salt induced precipitation. In the experimental group, BAECs were treated by extracellular protein in different concentrations (200, 300, 400, 500, 600 mug/mL) for 24 hours. In the control group, BAECs were cultured without extracellular protein. Furthermore, BAECs were exposed to 400 mug/mL extracellular protein for 6, 12, 24 and 36 hours, while BAECs in the control group were also cultured for 6, 12, 24 and 36 hours. Cell viabilities in both groups were determined by trypan blue staining. All the results were analyzed by non-paired t test with SPSS 10.0 software package. RESULTS: The viability of BAECs in the experimental group was significantly lower than that of the control group (P<0.05), which mean that the viability of BAECs decreased when cells treated with extracellular protein. As the concentration of extracellular protein increased, cell viability was reduced gradually. With the lapse of time (within 36 hours), the viability of BAECs in both groups declined. However, cell viability in the experimental group decreased significantly than that of the control group (P<0.05). The reduction of cell viability caused by extracellular protein was in a time dependent manner. CONCLUSIONS: Extracellular protein from P. gingivalis reduces the viability of bovine aortic endothelial cells in a dose and time dependent manner. Supported by National Natural Science Foundation of China (Grant No. 30471883).