Proliferation effect of mandibular condylar chondrocytes given the static tension-stress and/or TGF-β1 in vitro

The purpose of this study is to study the proliferous effect of mandibular condylar chondrocytes given static tension-stress and/or transforming growth factor-β₁ (TGF-β₁) in vitro. The fourth-passage condylar chondrocytes were harvested for this study, and a pulsatile cellular mechanical system was used to apply stress on cells. The proliferous effect of condylar chondrocytes given continuous static tension-stress and/or TGF-β₁ were examined by using flow cytometry. The experiment was divided into two parts. The first part was divided into 20 groups according to different TGF-β₁ dosage (0ng/ml, 0.1ng/ml, 1ng/ml and 10ng/ml) for 0, 6, 12, 18 and 24 hours respectively. The second part was divided into eight groups under continuous static tension-stress (0 or 5kPa) and different TGF-β₁ dosage (0ng/ml, 0.1ng/ml, 1ng/ml, 10ng/ml) for 12 hours. Experimental data was analyzed with repeated interclass analysis of variance The results showed that chondrocytes which were cultured under different TGF-β₁dose combined with 5kPa static tension-stress had multi-horn morphological characters, including a great quantity of chondrocytes with division growth.TGF-β₁ had a mitogenic effect on rat mandibular condyle chondrocytes at the concentrations of 0.1, 1 and 10ng/ml, and the mitogenic effect of TGF-β₁ to condylar chondrocytes were demonstrated after 12 to 18 hours, and the peak of mitogenic effects appeared at the 18th hour (P <0.05). The most active mitogenesis happened in the group whose chondrocytes was under continuous static tension-stress (5kPa) combined with TGF-β₁. These results proved that mechanical stimulus and TGF-β₁ in vitro could influence and regulate the growth of condylar chondrocytes.