Basic calcium phosphate crystals stimulate cell proliferation and collagenase message accumulation in cultured adult articular chondrocytes

Objective. To investigate BCP (basic calcium phosphate) crystal—stimulated mitogenesis and collagenase gene transcription in primary cultures of porcine chondrocytes. Methods. The role of protein kinases in BCP crystal—stimulated DNA synthesis was investigated using thymidine incorporation, kinase inhibitors, and protein kinase C (PKC) assays. Northern blot analysis was used to determine the levels of collagenase c‐fos and c‐jun message. Results. BCP crystals stimulated chondrocyte proliferation in a PKC‐dependent manner. Increased levels of collagenase message were preceded by an increased accumulation of c‐fos, but not c‐jun. Conclusion. BCP crystals could contribute to the abnormal chondrocyte proliferation and collagenase secretion observed in some rheumatic diseases.