Abstract
Objective: To evaluate the effect of epigallocatechin-3-gallate (EGCG) treatment on the proliferation and osteogenic differentiation of human periodontal ligament cell (hPDLC) and to explore the potential role of EGCG in promoting periodontal hard tissue regeneration. Methods: The hPDLC was isolated from periodontal ligament tissue obtained from freshly extracted human teeth. The effect of treatments with various concentrations of EGCG (0 μmol/L, 2 μmol/L, 4 μmol/L, 6 μmol/L, 8 μmol/L and 10 μmol/L) on cell proliferations were determined by cell counting kits (CCK) after 24-, 48- and 72-hour-incubations, respectively. Osteogenic differentiation abilities of hPDLCs were assessed by using alkaline phosphatase (ALP) activity tests after 7- and 14-day-incubations, respectively. The mineralized nodules were quantitatively examined and analyzed by using alizarin red staining after 21-day-incubation. The real-time PCR (RT-PCR) assays were conducted fordetecting the expressions of Runt related transcription factor-2 (Runx2), ALP and collagen type Ⅰ (COL Ⅰ) after 7-day-incubation. Results: Treatment with 4 μmol/L EGCG increased hDPLC proliferation at 24 h, while 8 μmol/L or 10 μmol/L EGCG treatment groups showed inhibiting effects at 24 h and 72 h, respectively. Findings of alizarin redstaining showed orange to red colored extracellular mineralized nodules in all groups. The the A values of 2, 4, 6, 8, 10 μmol/L EGCG groups were 0.119±0.001, 0.167±0.003, 0.173±0.003, 0.110±0.001 and 0.083±0.003, respectively. A values of 2-8 μmol/L EGCG groups were significantly higher than that of the control group, however there was no significant difference of the A values between10 μmol/L EGCG group and the control group (0.077±0.001). Treatments with 2-10 μmol/L EGCG could significantly increase the mRNA expressions of COL Ⅰ and ALP with the highest values in 4-6 μmol/L EGCG treatment groups. Although treatments with 4 and 6 μmol/L EGCG both could increase the mRNA expressions of Runx2, the result in 4 μmol/L group was much better than that of 6 μmol/L group. Conclusions: Treatment of 4 μmol/L EGCG could promote hPDLC proliferation at early stageand treatments with 4-6 μmol/L EGCG could significantly promote the osteogenesis of hPDLCs which might play a promising role in periodontal hard tissue regeneration.
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