小鼠肥胖不同阶段相关免疫器官恒定自然杀伤T细胞(iNKT)的频率和亚群变化

Changes in invariant nature kiler T(iNKT)cell percentages and subsets in immune organs of mice at different stages of obesity

目的采用高脂饮食喂养构建小鼠肥胖模型,观察恒定自然杀伤T细胞(iNKT)在肥胖不同阶段脂肪及相关组织中的频率及亚群变化,探讨iNKT细胞在肥胖脂肪组织慢性炎症中的作用。方法记录小鼠体重和精神状态以及葡萄糖耐量和胰岛素耐量的变化;苏木精-伊红(HE)染色观察脂肪组织病理变化;流式细胞术检测iNKT细胞和巨噬细胞频率和亚群的变化;CBA检测血清和脂肪组织淋巴细胞培养上清中细胞因子水平;Western blot检测脂肪组织中相关蛋白质的表达量差异。结果(1)高脂喂养4周后,脂肪细胞体积明显增大,炎性细胞浸润不明显;高脂喂养12周后,炎细胞浸润明显增多。(2)高脂喂养可致脂肪组织中iNKT细胞频率下降,iNKT1亚群比例增高,iNKT10亚群比例下降;胸腺iNKT1亚群比例升高,iNKT2亚群比例下降;脂肪组织中巨噬细胞频率及M1亚群比例增高,M2亚群比例下降,上述变化在高脂喂养12周组更为明显。(3)高脂喂养造成脂肪组织中E4BP4、精氨酸酶1(Arg-1)表达下降,诱导型一氧化氮合酶(iNOS)表达增高。(4)高脂喂养使小鼠血清和脂肪组织淋巴细胞培养上清中促炎性细胞因子明显增高,抑炎性细胞因子显著下降,且12周组变化更为明显。结论肥胖小鼠脂肪组织中iNKT1细胞亚群升高和iNKT10细胞亚群降低与M1型极化的增强可能存在密切关系,iNKT细胞亚群的失衡可能参与了肥胖小鼠脂肪组织慢性炎症的进展。

Objective To observe the changes in percentages and subsets of invariant nature kiler T(iNKT)cells in adipose and related tissues at different stages of obesity,and analyze the role of iNKT cells during chronic inflammation in adipose tissues in a mouse model of obesity established with high-fat diet.Methods Changes in mouse body weight,mental state,glucose tolerance and insulin tolerance were recorded.Hematoxylin and eosin(HE)staining was used to observe pathological changes in adipose tissues.Flow cytometry was performed to detect the percentages and subsets of iNKT cells as well as the percentages and subtypes of macrophages.The levels of cytokines in serum samples and the culture supernatants of lymphocytes in adipose tissues were detected with CBA.The expression of related proteins in adipose tissues was detected by Western blot.Results(1)The volume of adipose cells increased significantly after four weeks of high-fat feeding,but the infiltration of inflammatory cells was not obvious.Significantly increased infiltration of inflammatory cells was observed after 12 weeks of high-fat feeding.(2)High-fat feeding could reduce the percentage of iNKT cells,increase the proportion of iNKT1 subgroup and decrease the proportion of iNKT10 subgroup in adipose tissues.The proportion of iNKT1 subgroup in thymus increased,but that of iNKT2 subgroup decreased.The percentage of macrophages and the proportion of M1 subgroup in adipose tissues increased,while the proportion of M2 subgroup decreased,which were more obvious after 12 weeks of high-fat feeding.(3)High-fat feeding resulted in decreased expression of E4BP4 and arginase-1(Arg-1)in adipose tissues and increased expression of inducible nitric oxide synthase(iNOS).(4)High-fat feeding significantly increased the pro-inflammatory cytokines and decreased the anti-inflammatory cytokines in mouse serum and culture supernatants of lymphocytes in adipose tissues with more significant changes observed after 12 weeks of high-fat feeding.Conclusions Increased iNKT1 and decreased iNKT10 in obese adipose tissues might be closely related to the increased M1 polarization and the imbalance of iNKT subsets might be involved in the progression of chronic inflammation in obese adipose tissues.