激活视黄醇类X受体对氧化型低密度脂蛋白诱导小鼠巨噬细胞系RAW264.7向树突样细胞分化的影响

目的探讨激活核受体视黄醇类X受体（RXR）对氧化型低密度脂蛋白（ox—LDL）诱导巨噬细胞向树突状细胞分化的影响及其机制。方法小鼠巨噬细胞系RAW264．7经ox-LDL诱导48h后分化为树突样细胞,相差显微镜观察细胞形态,流式细胞仪检测细胞表面标志物,CM-H2DCFDA荧光探针测定细胞内活性氧浓度。结果ox—LDL诱导48h后,表达与树突状细胞免疫成熟和激活有关的细胞表面标志物CIMO、CD86、CD83、MHCClassⅡ和CD1d的RAW264．7细胞比例明显升高,同时给予天然型RXR特异性配体9-cisRA（10^-7mol／L）上述比例分别下降约47％、43％、48％、32％和17％,同时给予合成型RXR特异性配体SR11237（10^-6mol／L）上述比例分别下降约38％、38％、46％、36％和32％,并且均表现剂量依赖性。相差显微镜观察发现树突样细胞形态改变也得到部分抑制。ox-LDL引起细胞内活性氧浓度显著升高[平均荧光强度（MFI）38．24±4．20比4．46±0．39,P〈0．05],同时给予9．cisRA（10.mol／L）或SR11237（10^-6mol／L）MFI分别降低到12．60±1．52和17．89±1．91,较ox-LDL单独处理组差异有统计学意义（P〈0．05）。结论激活核受体RXR能够部分抑制ox-LDL诱导巨噬细胞向树突状细胞分化,其机制可能与减轻细胞氧化应激损伤有关。

Effect of retinoid X receptor activation on oxidized low-density lipoprotein induced cell differentiation of murine macrophage cell line into dendritic like cells

OBJECTIVE: To investigate the effect and related mechanism of retinoid X receptor (RXR) activation on oxidized low-density lipoprotein (ox-LDL) induced differentiation of macrophage into dendritic cell. METHODS: RAW264.7 murine macrophage cell line was cultured with ox-LDL for 48 h in the absence and presence of RXR activator 9-cisRA or SR11237. Cell morphology was observed by phase contrast microscope and cell surface markers involved in dendritic cell immune maturation and activation was analyzed by FACS. Cellular reactive oxygen species production was detected by CM-H2DCFDA fluorescent probe. RESULTS: ox-LDL-treated RAW264.7 murine macrophage cell line differentiated into dendritic like cells after 48 h and cell surface markers CD40, CD86, CD83, MHC Class II and CD1d were upregulated. These changes could be attenuated by cotreatment with 9-cisRA or SR11237. Upregulated cell surface markers CD40, CD86, CD83, MHC Class II and CD1d by ox-LDL were decreased about 47%, 43%, 48%, 32% and 17% respectively by 9-cisRA and 38%, 38%, 46%, 36% and 32% respectively by SR11237. The effect of 9-cisRA and SR11237 was dose dependent. Cellular reactive oxygen species were significantly increased in ox-LDL-treated RAW264.7 cells (MFI 38.24 +/- 4.20 vs. 4.46 +/- 0.39, P < 0.05) and which was significantly reduced by 9-cisRA (10(-7) mol/L) and SR11237 (10(-6) mol/L) to 12.60 +/- 1.52 and 17.89 +/- 1.91 respectively (all P < 0.05). CONCLUSION: RXR activation partly inhibits the differentiation of ox-LDL induced macrophage into dendritic cell by reducing oxidative stress injury.