Increased Bcl-2/p53 ratio in human osteoarthritic cartilage: a possible role in regulation of chondrocyte metabolism

Open Access
Publisher Website
Google Scholar
Abstract
Objective: To determine whether Bcl-2, p53, and Fas/CD95 help to control cartilage metabolism. Methods: Six normal and 14 osteoarthritic (OA) cartilage samples were examined, and two zones from each sample showing the least (Min) and most (Max) anatomical damage were selected. Chondrocytes were isolated by sequential enzymatic digestion and freshly processed. Bcl-2, p53, and Fas/CD95 expression was evaluated by immunofluorescence and FACS analysis; the cell cycle was analysed using propidium iodide, and chondrocyte proliferation assessed by [3H]thymidine incorporation. Results: Intracellular levels of Bcl-2 were significantly higher in Max (27.5%) than in Min (21%, p3H]thymidine uptake correlated positively with Bcl-2 (rs = 0.62, p = 0.009) and correlated inversely with p53 levels (rs = −0.55, p = 0.02). Conclusions: Bcl-2 and p53 play a part in apoptosis, but also help to regulate chondrocyte growth and differentiation. Whereas Bcl-2 promotes cell survival, p53 can arrest cell cycle. The data confirm that chondrocyte activity is enhanced in OA and suggest that the increased Bcl-2/p53 ratio sustains the metabolic boost of chondrocytes.