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Azerbaycan Saytlari

 »  Home  »  Endodontic Articles 5  »  Invasion of vascular cells in vitro by Porphyromonas endodontalis
Invasion of vascular cells in vitro by Porphyromonas endodontalis
Results.



Five laboratory strains of microorganisms ( P. endodontalis strain 35406, P. endodontalis strain R-41, P. endodontalis strain H11 a–e, P. intermedia strain 27, and P. nigrescens strain 9336) associated with endodontic infections were tested for the ability to invade primary cultures of endothelial and smooth muscle cells. Of these, only P. endodontalis ATCC 35406 was invasive (the CFU were higher than non-invasive E. coli MC1061) in the antibiotic protection assay (Fig. 1). The CFU of strain 35406 recovered following the antibiotic incubation was 1.8 0.6 10 4 in HCAEC. Although the invasive ability of P. endodontalis ATCC 35406 was approximately 10-fold less than P . gingivalis 381, it is considered moderately invasive according to the classification previously described (Dorn et al . 2000). Invasion was confirmed by transmission electron microscopy (Fig. 2). Although P. endodontalis is closely related to P. gingivalis , its intracellular location following invasion of HCAEC is different from the P. gingivalis vacuole. P . gingivalis is localized within autophagosomes, whereas P. endodontalis is located in large endosomes contained by a thin membrane. P. endodontalis ATCC 35406 also invaded CASMC (1.1 0.04 10 4 ) in the antibiotic protection assay.
All of the other strains tested had invasion levels below the non-invasive control E. coli MC1061. P. endodontalis strain R-41 and strain H11a–e were not invasive. Thus, the invasion ability of P. endodontalis varies between the strains. The type strain of P. nigrescens , the most frequently isolated BPB from endodontic lesions and a close relative of P. intermedia , was also not invasive.

Figure 1. Invasion of human coronary artery endothelial cells by black pigmenting bacteria associated with endodontic infections. P. gingivalis 381 and E. coli MC1061 were used as the positive and negative controls, respectively, since their invasive ability in these cell lines have been characterized previously (Dorn et al. 1999). Error bars represent the standard deviation (n = 3).

Invasion of human coronary artery endothelial cells by black pigmenting bacteria associated with endodontic infections

Figure 2. Transmission electron micrograph of internalized P. endodontalis. Internalized P. endodontalis (arrow) in HCAEC following a 90-minute infection.

Transmission electron micrograph of internalized P. endodontalis

Microorganisms from infected root canals were isolated, identified, and tested for their invasive ability. Four strains were positively identified as P. intermedia , Prevotella loeschii , and Prevotella tannerae (from two different patients). None of these four strains were invasive (Fig. 3). A fifth strain was isolated and was also noninvasive; however, tests could not definitively determine whether it was Prevotella melaninogenica or P. nigrescens . None of the bacteria isolated from infected root canals were invasive in the antibiotic protection assay.