Morphological Changes of Bovine Nasal Chondrocytes Induced by Interleukin-1α

OBJECTIVE: A study of the histological events under interleukin-1α (IL-lα) induction of bovine nasal cartilage (BNC) could result in useful data to better understand the mechanisms involved in tissue breakdown in joint diseases. The aim of this study was to investigate the effects of IL-lα on chondrocyte phenotype and extracellular matrix (ECM) changes in BNC explants. MATERIALS AND METHODS: In this experimental study, samples were divided into two groups. Group I (control group) BNC explants were cultured only in Dulbecco’s modified Eagle’s medium (DMEM). In group II, BNC explants were treated with IL-lα (10 ng/ ml) for 28 days. Then, samples were harvested on culture days 3, 7, 14, 21 and 28 and chondrocyte morphology and ECM alterations were assessed by invert microscopy and histology by hematoxylin and eosin (H&E) and Alcian blue. Cell viability was evaluated by the lactate dehydrogenase (LDH) assay test. Data were analyzed by the t test and p<0.05 was considered significant. RESULTS: IL-lα induced significant morphological changes in cartilage. In the presence of IL-lα, most chondrocytes transformed into a fibroblast-like morphology with a granular black point appearance. An increase in the cell: matrix ratio was observed and there were decreased numbers of chondrocytes.IL-lα induced breakdown of ECM. We observed partial degradation of ECM between days 7-14 and complete degradation occurred between days 21-28 of culture. The LDH levels increased. CONCLUSION: IL-1α induced morphological changes in chondrocytes and increased destruction of cartilage ECM. There was a parallel correlation between proteoglycan degradation and changes in chondrocyte morpholgy.