Interleukin-10 modulates pro-apoptotic effects of TNF-α in human articular chondrocytes in vitro

• Published in: Cytokine (Philadelphia, Pa.) Pa.), 2007-12, Vol.40 (3), p.226-234
• Main Authors: John, T., Müller, R.D., Oberholzer, A., Zreiqat, H., Kohl, B., Ertel, W., Hostmann, A., Tschoeke, S.K., Schulze-Tanzil, G.
• Format: Article
• Language: English
• Subjects: Aged; Apoptosis; Apoptosis - drug effects; Apoptosis - immunology; bcl-2-Associated X Protein - immunology; bcl-2-Associated X Protein - metabolism; Cartilage, Articular - cytology; Cartilage, Articular - immunology; Cartilage, Articular - metabolism; Caspases - immunology; Caspases - metabolism; Cell Survival - drug effects; Cell Survival - immunology; Cells, Cultured; Chondrocyte; Chondrocytes - cytology; Chondrocytes - immunology; Chondrocytes - metabolism; Collagen Type II - biosynthesis; Collagen Type II - immunology; Drug Antagonism; Female; Gene Expression Regulation - drug effects; Gene Expression Regulation - immunology; Humans; IL-10; Interleukin-10 - antagonists & inhibitors; Interleukin-10 - immunology; Interleukin-10 - metabolism; Interleukin-10 - pharmacology; Male; Middle Aged; Mitochondria - immunology; Mitochondria - metabolism; Recombinant Proteins - antagonists & inhibitors; Recombinant Proteins - immunology; Recombinant Proteins - metabolism; Recombinant Proteins - pharmacology; Time Factors; TNF-α; Tumor Necrosis Factor-alpha - antagonists & inhibitors; Tumor Necrosis Factor-alpha - biosynthesis; Tumor Necrosis Factor-alpha - immunology; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 1043-4666; 1096-0023
• DOI: 10.1016/j.cyto.2007.10.002

The aim of this study is to determine if there is an antagonistic effect between tumour necrosis factor (TNF)-α and the immunoregulatory interleukin (IL)-10 on chondrocytes survival. Serum-starved primary human articular chondrocytes were stimulated with either 10 ng/ml recombinant TNF-α, IL-10 or a combination of both (at 10 ng/ml each). Chondrocyte apoptosis was determined by measuring caspase-3/7, -8 and -9 activities using caspase assays. Mitochondrial apoptotic inducer bax, and the suppressor bcl-2 were evaluated using western blotting at 48 h. Results indicated that TNF-α increased caspase activities and resulted in a significant ( p = 0.001) increase in bax/bcl-2 ratio. Stimulation with IL-10 did not alter caspase activities, while co-treatment with IL-10 and TNF-α inhibited TNF-α induced caspase activities and significantly ( p > 0.004) impaired bax/bcl-2 ratio. At 24 h, mRNA levels for collagen type II, TNF-α and IL-10 were determined using real-time RT-PCR. Stimulation with TNF-α or TNF-α and IL-10 significantly inhibited collagen type II and increased IL-10 and TNF-α mRNA expression. IL-10 modulated the pro-apoptotic capacity of TNF-α in chondrocytes as shown by the decrease in caspase activities and bax/bcl-2 ratio compared to TNF-α stimulated chondrocytes, suggesting a mostly antagonistic interplay of IL-10 and TNF-α on mitochondrial apoptotic pathways.