Schuerwegh A J, Dombrecht E J, Stevens W J, Van Offel J F, Bridts C H, De Clerck L S
Department of Immunology, Allergology and Rheumatology, University of Antwerp, Belgium
Osteoarthritis Cartilage. 2003 Sep;11(9):681-7. doi: 10.1016/s1063-4584(03)00156-0.
Cytokines produced by inflammatory cells play a pivotal role in synovial inflammation and joint destruction in rheumatoid arthritis. To investigate the influence of pro-inflammatory cytokines (IL-1 alpha, IL-6, TNF-alpha, IFN-gamma) and subsequently the possible beneficial role of an anti-inflammatory cytokine (IL-4) on chondrocyte viability (necrosis/apoptosis), proliferation and nitric oxide (NO) production.
Primary bovine chondrocytes were cultured until monolayers were obtained. Cells were incubated with cytokines (IL-1 alpha, IFN-gamma, TNF-alpha, IL-4, IL-6) at 0.1, 1, 10 and 100 ng/mL. After 48 h, the viability of the chondrocytes was measured flow cytometrically with propidium iodide. Proliferation was determined by the incorporation of tritiated thymidine. The morphology of the chondrocytes, including presence of apoptotic nuclei, was evaluated by a May-Grünwald-Giemsa staining. In addition, the number of apoptotic chondrocytes was detected flow cytometrically with a TUNEL technique and annexin-V/propidium iodide staining. NO production was evaluated using a spectrophotometric assay, based upon the Griess reaction.
The viability and proliferation of bovine chondrocytes decreased after incubation with 100 ng/mL IL-1 alpha, TNF-alpha or IFN-gamma. In contrast, incubation of chondrocytes with IL-4 or IL-6 had no influence on the viability or the proliferation of cells. IL-1 alpha was able to enhance NO production in a dose dependent manner. IFN-gamma and TNF-alpha induced NO production only at the highest concentration (100 ng/mL), whereas IL-4 and IL-6 did not. There was a dose dependent increase in apoptosis of bovine chondrocytes cultured in the presence of IL-1 alpha and TNF-alpha. This effect could not be prevented by preincubation with IL-4. Preincubation with IL-4 diminished IL-1 alpha and TNF-alpha induced NO production and increased proliferation of chondrocytes. In an additional experiment, incubation of human chondrocytes with anti-Fas did not induce apoptosis as measured by annexin-V/propidium iodide staining.
Pro-inflammatory cytokines are able to induce apoptosis, whereas IL-4 as an anti-inflammatory cytokine can inhibit the effect of IL-1 alpha and TNF-alpha on NO production and proliferation of bovine chondrocytes.
炎症细胞产生的细胞因子在类风湿关节炎的滑膜炎症和关节破坏中起关键作用。研究促炎细胞因子（IL-1α、IL-6、TNF-α、IFN-γ）的影响，以及随后抗炎细胞因子（IL-4）对软骨细胞活力（坏死/凋亡）、增殖和一氧化氮（NO）产生的可能有益作用。
原代牛软骨细胞培养至形成单层。细胞分别与浓度为0.1、1、10和100 ng/mL的细胞因子（IL-1α、IFN-γ、TNF-α、IL-4、IL-6）孵育。48小时后，用碘化丙啶通过流式细胞术检测软骨细胞的活力。通过掺入氚标记的胸腺嘧啶核苷来测定增殖情况。用May-Grünwald-Giemsa染色评估软骨细胞的形态，包括凋亡细胞核的存在情况。此外，用TUNEL技术和膜联蛋白-V/碘化丙啶染色通过流式细胞术检测凋亡软骨细胞的数量。基于Griess反应，用分光光度法测定NO的产生。
与100 ng/mL的IL-1α、TNF-α或IFN-γ孵育后，牛软骨细胞的活力和增殖能力下降。相反，软骨细胞与IL-4或IL-6孵育对细胞活力或增殖没有影响。IL-1α能够以剂量依赖的方式增强NO的产生。IFN-γ和TNF-α仅在最高浓度（100 ng/mL）时诱导NO产生，而IL-4和IL-6则不能。在IL-1α和TNF-α存在的情况下培养的牛软骨细胞凋亡呈剂量依赖性增加。用IL-4预孵育不能预防这种效应。用IL-4预孵育可减少IL-1α和TNF-α诱导的NO产生，并增加软骨细胞的增殖。在另一项实验中，用抗Fas处理人软骨细胞后，通过膜联蛋白-V/碘化丙啶染色检测未诱导凋亡。
促炎细胞因子能够诱导凋亡，而IL-4作为抗炎细胞因子可以抑制IL-1α和TNF-α对牛软骨细胞NO产生和增殖的影响。
