Effect of type I collagen on TLR-3 induced MMP-13 expression in human periodontal ligament fibroblasts

Background: This study examined the effects of type I collagen, alone and in combination with poly I:C-a toll-like receptor 3 (TLR3) agonist-on matrix metalloproteinase-13 (MMP-13) expression and wound healing in human periodontal ligament (hPDL) fibroblasts. Methods: hPDL fibroblasts were cultured and divided into four treatment groups: control, type I collagen (50 μg/mL), poly I:C (10 μg/mL), and a combination of type I collagen with poly I:C. Cytotoxicity was evaluated using the MTT assay. Cell migration was assessed via scratch assay at 0, 24, and 48 h. MMP-13 expression was quantified at both the mRNA and protein levels by real-time PCR and ELISA, respectively. Results: After 24 h, the MTT assay indicated that none of the four treatment groups exhibited cytotoxicity toward hPDL fibroblasts. In the scratch assay at 24 and 48 h, type I collagen group demonstrated the fastest wound closure, whereas the poly I:C group showed the slowest migration. Regarding MMP-13 expression, the combination group displayed the highest mRNA levels, while ELISA revealed that both the combination and poly I:C groups had the greatest protein expression relative to the control. Conclusion: This study provides evidence for an interaction between extracellular matrix signals and innate immune activation. Type I collagen promoted hPDL fibroblast migration, whereas poly I:C-a TLR3 agonist-upregulated MMP-13 expression, with the greatest effect observed in combination with collagen.