Age dependent gene expression pattern of hPDLF

Objectives: Human periodontal ligament fibroblasts (hPDLF) are very important for curing the periodontal tissue because they can be transformed into various cells. This study examined the expression levels of MMP-1, TIMP-1, periodontal ligament specific PDLs22, Type I collagen, Fibronectin, TIMP-2, telomerase mRNA in the replicative senescence of hPDLF. Methods: The periodontal ligament tissue was obtained from periodontally healthy and non-carious human teeth that had been extracted for orthodontic reasons at the Chosun University Hospital of Dentistry with the donors' informed consent. The hPDLF cells were cultured in a medium containing Dulbecco's modified Eagle medium (DMEM; DMEM, Gibco BRL, USA) supplemented with 10% fetal bovine serum (FBS, Gibco BRL, USA) at 37°C in humidified air with 5% CO2. For reverse transcription-polymerase chain reaction (RT-PCR) analysis, the total RNA of the 2nd, 4th, 8th, 16th, 18th, and 21st final passage cells was extracted using a Trizol Reagent (Invitrogen, USA) in the replicative hPDL cells. The 2nd passage cells were used as the control, and the 4th, 8th, 16th, 18th, and 21st final passage cells were used as the experimental group. β-actin was used as the internal control for RT-PCR. Results: RT PCR revealed that PDLs22 mRNA was expressed in the young hPDLF of the 2nd, 4th, and 8th passage, TIMP-1 mRNA was expressed in young hPDLF of in the 2nd and 4th passage. Type 1 collagen mRNA was expressed in all passages except in the final passage. There was a tendency for MMP-1 mRNA to be only weakly expressed after 18 passages. TIMP-2 and telomerase mRNA were not expressed. Conclusions: PDLs22, Type 1 collagen, Fibronectin, MMP-1. and TIMP-1 mRNA in hPDLF showed age dependent expression patterns. This study was supported by a grant of the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea (03-PJ1-PG1-CH08-0001).