Palatal mucosa derived fibroblasts present an adaptive behavior regarding cytokine secretion when grafted onto the gingival margin

Background: Considering that grafted gingival tissue might have to be adapted to the receptor area and that fibroblasts have the ability to respond to bacterial stimuli through the release of various cytokines, this study investigated whether fibroblasts from the palatal mucosa behave differently when grafted onto the gingival margin regarding cytokine secretion. Methods: Biopsies from the palatal mucosa were collected at the time of free gingival graft surgery, and after four months re-collection was performed upon surgery for root coverage. Fibroblasts were isolated by the explant technique, cultured and stimulated with Porphyromonas gingivalis (Pg) and Escherichia coli (Ec) LPS for 24 or 48 h for comparative evaluation of the secretion of cytokines and chemokines, such as IL-6, IL-8/CXCL8, MIP-1 alpha/CCL3, TGF-beta, VEGF and CXCL16. Unstimulated cells were used as the control group. Cells were tested for viability through MTT assay, and secretion of cytokines and chemokines was evaluated in the cell supernatants by Enzyme-Linked Immunosorbent Assay (ELISA). Results: Fibroblasts from the palatal mucosa maintained the same secretion pattern of IL-6 when grafted onto the gingival margin. On the contrary, fibroblasts from the marginal gingival graft showed increased secretion of IL-8/CXCL8 even in the absence of stimulation. Interestingly, MIP-1 alpha/CCL3 secretion by fibroblasts from the marginal gingival graft was significantly increased after 48 hours of stimulation with Pg LPS and after 24 h with Ec LPS. Only fibroblasts from the marginal gingival graft showed secretion of TGF-beta. VEGF and CXCL16 secretion were not detected by both subsets of fibroblasts. Conclusion: Fibroblasts from the palatal mucosa seem to be adapted to local conditions of the site microenvironment when grafted onto the gingival marginal area. This evidence supports the effective participation of fibroblasts in the homeostasis of the marginal periodontium through secretion modulation of important inflammatory mediators.