The Efficacy of Salivary Histatin-1 Protein in Wound Closure of Nicotine Treated Human Periodontal Ligament Fibroblast Cells – in Vitro Study

Objectives: The aims of this study were to investigate the efficacy of Histatin-1 in wound closure as well as effects on gene expression of nicotine-treated human Periodontal Ligament Fibroblast cells (HPDL) in vitro. Design: HPDL grown in 2.5% culture medium treated with 10 ng/ml Histatin - 1 in the presence/absence of 0.5 mu M nicotine were subjected to wound assay and migration was studied at 0 h, 6 h, 12 h and 24 h. Cells grown in 2.5% medium served as control. Cell migration was studied by wound gap and transwell migration assays. The effect of Histatin-1 on expression of matrix metalloproteinase 8 (MMP-8), insulin-like growth factor 1 (IGF-1), transforming growth factor beta (TGF-beta), collagen type I (COL1) and plasminogen activator inhibitor 1 (PAI-1) were studied. Results: Histatin-1 treatment significantly decreased percentage wound gap at 12 h (62.96 & PLUSMN; 3.22 vs 79.23 & PLUSMN; 1.73; p < 0.05) and at 24 h (38.78 & PLUSMN; 7.59 vs 75.21 & PLUSMN; 4.94; p < 0.001) compared with controls. In nicotine+Histatin-1 treated cells, wound gap decreased to 70.2 & PLUSMN; 2.9% (p < 0.01) at 24 h compared to nicotine alone in which 82 & PLUSMN; 1.64% of wound gap was retained. Transwell migration assays showed significant migration of HPDL with Histatin-1 (p < 0.05). Gene expression demonstrated significant upregulation for IGF-1, TGF beta, COL1 and PAI-1 with Histatin-1. Conclusion: Histatin-1 significantly mitigated the effect of nicotine in wound healing assay involving HPDL fibroblast cells at 24 h. Histatin-1 aided wound closure is attributed to the upregulation of IGF-1, TGF beta, COL1, and PAI-1 genes.