The aim of this study was to evaluate the effects of H2O2 and ascorbic acid on matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase (TIMP: TIMP-1, TIMP-2), Type 1 collagen, fibronectin, and PDLs22 level in human periodontal ligament fibroblasts (hPDLF) via reverse transcription-polymerase chain reaction (RT-PCR).

hPDLF was obtained from a healthy periodontium and cultured in Dulbecco's modified Eagles's medium plus 10% fetal bone serum.

The concentration of ascorbic acid in hPDLF was 50 µg/ml, and that of H₂O₂ in hPDLF was 0.03% and 0.00003%. Ascorbic acid only, H₂O₂ only and mixture of ascorbic acid and H₂O₂ were applied with hPDLF for 1-, 3-, and 30-min., respectively. The gene expression of MMP-1-, TIMP-1-, TIMP-2-, Type 1 collagen-, fibronectin-, and PDLs22-mRNA in hPDLF was analysed via RT-PCR.

The results were as follows;

1. hPDLF in response to 30-min. incubation with 0.03% H2O2 did not show any gene expression.

2. In all the experimental groups, the gene expression of fibronectin mRNA showed the decreased tendency compared to control.

3. In all the experimental groups, the gene expression of TIMP-1 mRNA showed the tendency similar to control.

4. hPDLF in response to 30-min. incubation with 0.03% H2O2 and ascorbic acid increased mRNA induction for MMP-1.

5. In all the experimental groups, hPDLF increased mRNA induction for PDLs22, collagen type I, and TIMP-2 compared to control.

Within the limited experiments, H₂O₂ and ascorbic acid increased mRNA induction for PDLs22, collagen type I, and TIMP-2 in hPDLF. More research will be needed in order to confirm the relative importance of the different roles of ROS and antioxidants in hPDLF from a periodontal regeneration or repair standpoint.