白介素2和肿瘤坏死因子α对大鼠C6胶质瘤细胞产生一氧化氮的影响

用Griess法检测细胞培养上清中NO^÷₂含量作为反映细胞产生一氧化氮(NO)量的指标，观察细菌脂多糖(LPS)，干扰素γ(IFN-γ)，肿瘤坏死因子α(TNF-α)及白介素2(IL-2)对大鼠C6胶质瘤细胞产生NO的影响. 结果C6细胞于体外培养8 h时可自发产生NO，24 h达峰值(17.5±1.9 vs溶剂对照组6.5±1.9 μmol·L^-1)，48 h仍有产生. 在所用剂量范围，上述因素单独作用24 h均不影响C6产生NO，而5-500 kU·L^-1 IL-2与0.5 mg·L^-1 LPS或50 kU·L^-1 IFN-γ合用可增强C6产生NO(10.6-13.4 vs 7.2 μmol·L^-1)，LPS，IFN-γ及TNF-α三者合用亦有一定促进C6产生NO作用. 提示炎性刺激与炎性细胞因子共同作用可促进中枢神经胶质细胞产生NO.

Effects of interleukin 2 and tumor necrosis factor α on nitric oxide production from rat C6 glioma cells

Activated microglia and astrocytes synthesize nitric oxide(NO) and pre- inflammatory cytokines such as IL-1, IL-2, IL-6 and TNF-α. To investigate which one of these mediators plays a key role in the proposed inflammatory cascade in Alzheimer′s disease, NO production represented by nitrite concentration in supernatants of cultured rat C6 glioma cells was assayed with Griess reaction, and the effects of IL-2 and TNF- α on NO production from C6 glioma cells were studied. The results showed that when cultured without stimulation, C6 glioma cells produced NO which started at 8 h and reached peak concentration at 24 h(17.5±1.9 vs medium control 6.5±1.9 μmol·L^-1). The NO production was not affected by the addition of 0.01-1 mg·L^-1 LPS, 10-1000 kU·L^-1 IFN-γ, IL-2 or TNF-α. In the presence of 0.5 mg·L^-1 LPS or 50 kU·L^-1 IFN-γ, IL-2 at 5-500 kU·L^-1 enhanced NO production (10.6-13.4 vs 7.2 μmol·L^-1). In the presence of 0.33 mg·L^-1 LPS+33 kU·L^-1 IFN- γ, C6 glioma cells cultured for 6 h with 33 kU·L^-1 TNF- α produced more NO than the control (17.5 vs 10.4 μmol·L^-1). The results suggest that the combination of pre inflammatory cytokines and infectious stimuli enhance NO production from CNS glial cells.