Photodynamic effects on human periodontal-related cells in vitro

• We evaluated photodynamic effect on human periodontal cells.
• PDT induced time-dependent growth of these cells.
• PDT induced time-dependent attachment of these cells.
• PDT induced time-dependent Type I collagen synthesis of these cells.
• PDT induced an increase in the ALP activity in periodontal ligament cells.

SummaryBackgroundPhotodynamic therapy (PDT) may be especially effective in combination with conventional periodontal therapy by its antimicrobial activities, but PDT may also exhibit other mechanisms that promote the healing of periodontal tissue. Therefore, the purpose of the present study was to evaluate the photodynamic effect of PDT on human periodontal ligament cells (hPDLCs) and human gingival fibroblasts (hFBs) in vitro and other possible mechanisms to promote periodontal healing.MethodsThe proliferation of hPDLCs and hFBs was assessed by MTT assay. Cell attachment on cementum slices of hPDLCs and hFBs was evaluated by MTT assay. Type I collagen synthesis of hPDLCs and hFBs was analyzed using enzyme linked immunosorbent assay. The alkaline phosphatase (ALP) activity in hPDLCs was measured by p-nitrophenyl phosphate substrate reactions.ResultsPDT treatment induced constant time-dependent growth of hPDLCs and hFBs at 24 h, 72 h and 6 days (P < 0.05). PDT treatment also promoted time-dependent hPDLCs and hFBs attachment on the cementum slices at 24 h, 72 h and 6 days compared to the controlled cells (P < 0.05). Type I collagen synthesis of hPDLCs and hFBs was markedly stimulated by PDT in a time-dependent manner (P < 0.05). Likewise, a significant increase in the specific ALP activity in hPDLCs was observed (P < 0.05).ConclusionsThe findings of this study indicate that PDT exhibited no cytotoxicity to hPDLCs or hFBs. Instead, it stimulated proliferation, attachment and collagen synthesis of hPDLCs and hFBs and ALP activity of hPDLCs. These effects might signal similar PDT activity on periodontal-related cells, and expanding the scope of its potential therapeutic utilization is very appealing.