Effects of Porphyromonas gingivalis on human gingival fibroblasts from healthy and inflamed tissues

Background and Objective: This study compared the ability of human gingival fibroblasts (HGFs) isolated from healthy and inflamed gingival tissues to degrade collagen in the presence and absence of Porphyromonas gingivalis supernatant. Material and Methods: Human gingival fibroblasts were cultured from explants of 21 healthy and 21 inflamed periodontal tissues. The HGFs that grew out of the explants were seeded in the center of six-well plates coated with collagen in the presence and absence of 10% P. gingivalis supernatant. An inflamed and a healthy cell line were also evaluated with Arg-gingipain. After 6 days, Coomassie Blue was used to visualize the collagen cleavage. Results: The collagen was totally cleaved in 12 (aggressive) of the 21 cell lines isolated from the inflamed tissues in the presence of P. gingivalis. The remaining nine cell lines (non-aggressive) cleaved only the collagen underneath the cell colonies in the presence of P. gingivalis. Of the healthy tissues, five (aggressive) of the 21 cell lines cleaved all the collagen and 16 cell lines (non-aggressive) only cleaved the collagen underneath the cell colonies in the presence of P. gingivalis. All the collagen was cleaved by an aggressive cell line and only the collagen underneath the cell colonies was cleaved by a non-aggressive cell line in the presence of Arg-gingipain. Conclusion: The collagen in the wells was more readily cleaved by the inflamed than by the healthy cell lines, and the difference was statistically significant (p = 0.0278). Arg-gingipain gave identical results to the P. gingivalis supernatant.