高脂食物和K/BxN血清对ApoE基因敲除小鼠免疫系统的影响

Effect of high fat diet and K/BxN serum on the immune system of ApoE knockout mice

目的检测高脂食物和K/BxN血清对ApoE基因敲除(ApoE^(-/-))小鼠免疫细胞分布的影响。方法 ApoE^(-/-)小鼠从8周龄开始饲喂高脂食物,17周龄时腹腔注射抗6-磷酸葡萄糖异构酶(glucose-6-phosphate isomerase,GPI)抗体呈阳性的K/BxN血清,每周注射一次,每次注射0.2 mL。对照组饲喂普通食物,用同样的方法注射K/BxN血清。分别于注射K/BxN血清前后,ELISA法检测小鼠血脂水平变化,游标卡尺测量踝关节肿胀程度。高脂食物和K/BxN血清处理至26周龄时分离脾脏细胞和骨髓细胞,经流式抗体染色后,流式细胞术分析免疫细胞的分布情况。结果 ApoE^(-/-)小鼠腹腔注射K/BxN血清前后,饲喂高脂食物的ApoE^(-/-)小鼠血清低密度脂蛋白胆固醇(LDL-C)浓度,总胆固醇(TCHO)浓度和甘油三酯(TG)浓度均显著升高,主动脉瓣根部斑块面积显著增加,提示无论是否注射K/BxN血清,高脂食物都能使ApoE^(-/-)小鼠产生动脉硬化症状,且比饲喂普通食物的ApoE^(-/-)小鼠更严重。腹腔注射K/BxN血清前,各组ApoE^(-/-)小鼠踝关节和关节炎评分(clinical score)均处于正常水平,腹腔注射K/BxN血清后,饲喂高脂食物的ApoE^(-/-)小鼠踝关节宽度和关节炎评分均低于饲喂普通食物的ApoE^(-/-)小鼠。流式检测结果显示,饲喂高脂食物后注射K/BxN血清使ApoE^(-/-)小鼠脾脏和骨髓的CD3^+T细胞和CD19^+B细胞下调,CD11b^+巨噬细胞上调。结论高脂食物和K/BxN血清引起ApoE^(-/-)小鼠脾脏和骨髓的CD3^+T细胞和CD19^+B细胞下调,CD11b^+巨噬细胞上调,导致ApoE^(-/-)小鼠的动脉硬化症状加重,关节炎症状减轻。

Objective To detect the effect of high fat diet and K/BxN serum on the distribution of immune cells in ApoE gene knockout(ApoE-/-) mice. Methods ApoE-/- mice were fed with high fat diet(HFD) from 8 weeks of age, then the K/BxN serum whose anti-glucose-6-phosphate isomerase(GPI) antibodies were positive was injected intra-peritoneally once a week, with each injection of 0.2 mL, from 17 to 26 weeks of age. The control group was fed with ordinary diet(CD) and injected the K/BxN serum in the same way. The level of blood lipid was analysed by ELISA, and the ankle swelling was measured by vernier caliper before and after the K/BxN serum was injected intra-peritoneally. The splenocytes and bone marrow cells of ApoE-/-mice were isolated and stained by flow antibodies at 26 weeks of age, then detected by flow cytometry. Results Serum LDL-C, TCHO and TG levels of ApoE-/- mice were significantly increased before and after K/BxN serum was injected, and the areas of atherosclerotic plaques were significantly increased in aortic roots after K/BxN serum injected, suggested that whether K/BxN serum was injected, HFD could induce atherosclerosis of ApoE-/- mice, and the atherosclerotic symptom of ApoE-/- mice fed with HFD was more severe than the CD treated group.The ankle width and clinical scores showed that the ankle swelling of ApoE-/- mice was normal before K/BxN serum injected. However, ApoE-/- mice fed with HFD had lower joint width and clinical score than ApoE-/- mice fed with CD after K/BxN serum injected. The flowcytometry analysis showed that HFD down-regulates CD3+T cells and CD19+B cells, up-regulates CD11 b+ macrophages in splenocytes and bone marrow cells. Conclusions HFD down-regulates CD3+T cells and CD19+B cells, up-regulates CD11 b+ macrophages in splenocytes and bone marrow cells, so aggravates the atherosclerosis and relieves arthritis of ApoE-/- mice.