Transforming Growth Factor-β1 Preserves Bovine Nasal Cartilage against Degradation Induced by Interleukin-1α in Explant Culture

Chondrocytes and their differentiation play a central role in joint diseases. Effect of the transforming growth factor (TGF)-β1 on chondrocyte characteristics and differentiation is not clearly understood. This study was undertaken to investigate the effects of TGF-β1 on tissue characteristics and morphology of chondrocytes against degradation induced by interleukin (IL)-lα in bovine nasal cartilage (BNC) explant culture.
BNC explants were cultured in DMEM and samples were divided into four groups. In group A (control); samples were only cultured in DMEM and group B; was treated with IL-1α (10 ng/ml), group C; treated with TGF-β1 (10 ng/ml) and group D; treated with IL-1α (10 ng/ml) TGF-β1 (10 ng/ml) for 14 days. At days 3, 7 and 14 the media were collected and replaced with fresh media. Then, samples were harvested on days 3, 7 and 14 and chondrocyte morphology was assessed by invert microscopy. We used Masson's Trichrome stain to visualize collagen distribution and synthesis, and Safranin O and Alician blue to highlight the proteoglycan content.
In the presence of IL-lα, most of the chondrocytes were transformed into fibroblast-like morphology with pyknotic nuclei at day 14 and proteoglycan and collagen in extracellular matrix (ECM) were destructed at this time. In the presence of TGF-β1, chondrocytes preserved their ordinary normal features. Also, TGF-β1 inhibited collagen and proteoglycan destruction and cartilage ECM showed normal characteristics.
IL-1α induced significant morphological changes in chondrocytes and increased the destruction of ECM. TGF-β1 could strongly preserves cartilage from IL-1α degradation effects.