[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.