Proliferation Effect of Mandibular Condylar Chondrocytes Given The Static Tension-Stress and/or TGF-β1 In Vitro

Abstract

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.