Experimental Study On The Impact Of Porphyromonas Gingivalis On Vascular Smooth Muscle Cells

[Objective]:To investigate the affection of the Porphyromonas gingivalis(P.g) supernatant in the proliferation and migration of the cultured rabbit vascular smooth muscle cells(VSMCs) and the synthesis and secretion of IL-1βand IL-6, provide the laboratory evidence for the relationship between periodontal disease and atherosclerosis.[Method]:Tissue explant method of primary cultured VSMCs was identified by a-actin immunohistochemistry and transmission electron microscopy. Then we added the original concentration and diluted for 1/2,1/4,1/8,1/16,1/32 times P.g supernatant into the VSMCs and detected by MTT for testing the affection of the proliferation of the VMSCs; according to the results of MTT, we chose a concentration of 4.3×106CFU/ml of P.g supernatant stimulation VMSCs, at 12h,24h,48h, the cell culture supernatant were extracted, detected by ELISA in culture supernatant of IL-1β, IL-6 levels; with 4.3×106CFU/ml of the P.g supernatant stimulation VSMCs, at 12h, 24h,48h, the RT-PCR were used to observe the gene express of IL-1β, IL-6; with 4.3×106CFU/ml of the P.g supernatant stimulation VSMCs, we test the distance of the VSMCs in 7 days to find out the effection of P.g supernatant to the migration of the VSMCs. Analysis the dates by statistical methods.[Results]:The results showed that the concentration which is higher than 4.3×106CFU/ml P.g supernatants can inhibit VSMCs proliferation (p<0.05), the inhibition was concentration dependent and concentration of less than 4.3×106 CFU/ml of P.g on clear on the proliferation of VSMCs had no significant effect (p> 0.05); The migration shows that after wipe some cells with 4.3×106CFU/ml of P.g supernatant stimulation, before the 4d cell migration distance was greater than the control group (p<0.05), starting from 5th day experimental group and control group, no significant difference in migration distance (p> 0.05); with 4.3×106CFU/ml the P.g supernatant stimulated VSMCs 12h after within the cell culture supernatant levels of both IL-1βand IL-6 compared with the control group no significant difference (p> 0.05), stimulated of 24h, the culture supernatant IL-1βlevels were significantly lower than the control group (p<0.05) and the IL-6 levels were significantly higher than the control group (p<0.05).48h after stimulated, culture supernatant levels of IL-1βwithin the control group with no difference (p<0.05) and the IL-6's levels decreased but still significantly higher than the control group (p<0.05); by RT-PCR analysis showed that the P.g 4.3×106CFU/ml supernatant stimulation VSMCs 12h,24h,48h after cells were IL-1β, IL-6 gene expression. At 24h after the P.g supernatant stimulated, the expression of IL-1βdeclined and the IL-6's expression increased. [Conclusion]:P.g supernatant has inhibitory effect on the proliferation of VSMCs. At the first 4d of the intervertion, At 24h the superment inhibit the synthesis and secretion of IL-1βand increase the synthesis and secretion of IL-6. These result releave that the P.g infection may be play an important role in the occurrence and development of the Atherosclerosis(AS), This may be one of the bridge between periodontitis and AS.