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%, p,0.01) OA or normal chondrocytes (18.5%, p,0.01). Intracellular p53 expression was significantly decreased in Max (25.5%) compared with Min (37%, p,0.01) OA or normal cartilage (41.5%, p,0.05). Fas/CD95 receptor expression on surface chondrocytes did not significantly differ between OA and normal cartilage. Cell cycle analysis showed that the proportion of activated chondrocytes in the S phase was significantly higher in Max (69%) than in Min (49%) OA or normal cartilage (43%). The prevalence of proliferating chondrocytes progressively increased according to the degree of OA damage (mean (SEM) Min 1247 (260), Max 2423 (460), p,0.05). Chondrocyte [3H]thymidine uptake correlated positively with Bcl-2 (rs = 0.62, p = 0.009) and correlated inversely with p53 levels (rs =20.55, 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.

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

IANNONE, Florenzo;SCIOSCIA, CRESCENZIO;LAPADULA, Giovanni
2005-01-01

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%, p,0.01) OA or normal chondrocytes (18.5%, p,0.01). Intracellular p53 expression was significantly decreased in Max (25.5%) compared with Min (37%, p,0.01) OA or normal cartilage (41.5%, p,0.05). Fas/CD95 receptor expression on surface chondrocytes did not significantly differ between OA and normal cartilage. Cell cycle analysis showed that the proportion of activated chondrocytes in the S phase was significantly higher in Max (69%) than in Min (49%) OA or normal cartilage (43%). The prevalence of proliferating chondrocytes progressively increased according to the degree of OA damage (mean (SEM) Min 1247 (260), Max 2423 (460), p,0.05). Chondrocyte [3H]thymidine uptake correlated positively with Bcl-2 (rs = 0.62, p = 0.009) and correlated inversely with p53 levels (rs =20.55, 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.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/122305
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 34
  • ???jsp.display-item.citation.isi??? 30
social impact