Immortalized hPDL cell lines provided by Dr Takada (Hiroshima University) were cultured in α-minimum essential medium (α-MEM; Invitrogen, Grand Island, NY, USA) with 10% fetal bovine serum (FBS) plus penicillin G solution (10 U/ml) and streptomycin (10 mg/ml) in a humidified atmosphere of 5% CO2 at 37°. Telomerase catalytic subunit hTERT gene-immortalized human periodontal ligament (HPDL) cells were derived by transfecting primary cultured hPDL cells from a healthy premolar extracted for orthodontic treatment, as described previously [25,26]. These immortalized hPDL cells are similar to those in primary PDL-derived cells, and could be a model for the investigation of factors contributing to inflammation and differentiation of PDL

cells GSK2126458 [17,22]. For experiments, the cells were seeded into culture dishes and then cultured in DMEM containing 10% FBS for 3 days until 70% confluent. Subsequently, the cells were exposed to MS. All treatments were performed in triplicate. Human PDL cells (3 × 105/well) were subcultured into six-well, 35-mm flexible-bottomed

Uniflex culture plates with a centrally located this website rectangular portion (15·25 mm × 24·18 mm) coated with type I collagen designed to provide a uniform uni-axial strain, and subjected to an intermittent deformation of 3, 6, 12 or 15% of maximum stretch for 2·5 s followed by 2·5 s of relaxation (12 cycle/min 24 h) with a Flexercell FX-4000 Strain Unit (Flexcell Corporation, Hillsborough, NC, USA), according to the manufacturer’s instructions. siRNA-annealed oligonucleotide duplexes for SIRT1 (sequence 5′->3′ sense: GAUGAAGUUGACCUCCUCAtt; anti-sense: UGAGGAGGUCAACUUCAUCtt) and negative control (catalogue no. SN-1003) were purchased from Bioneer (Daejeon, South Korea) and PDL cells were transfected using lipofectamine 2000 (Gibco BRL), following the manufacturer’s instructions. After applying the MS, Loperamide total RNA was isolated from the cells using Trizol reagent (Invitrogen Life Technologies, Gaithersburg, MD, USA), according to the manufacturer’s instructions. Briefly, 1 µg of RNA isolated from each culture was reverse-transcribed using oligo(dT)15

primers (Roche Diagnostics, Mannheim, Germany) and AccuPower RT PreMix (Bioneer), according to the manufacturer’s protocols. An amount of cDNA equivalent to 25 ng of total RNA was then subjected to PCR. The primers used for cDNA amplification are listed in Table 1. PCR products were subjected to electrophoresis on 1·2% agarose gel and were stained with ethidium bromide. An equal volume of ×2 sodium dodecyl sulphide (SDS) sample buffer was added and the samples were then boiled for 5 min. Samples (40 µg) were subjected to electrophoresis on 12% SDS-polyacrylamide gels for 2 h at 20 mA and then transferred onto nitrocellulose. The membrane was incubated for 1 h in 5% (wt/vol) dried milk protein in phosphate-buffered saline (PBS) containing 0·05% (vol/vol) Tween-20, washed in PBS and then incubated for 1 h in the presence of primary antibody (1:1000).