吲哚胺2,3-双加氧酶在甲状腺相关性眼病中的变化

Change of indoleamine 2,3-dioxygenase in thyroid associated ophthalmopathy

目的探讨吲哚胺2,3-双加氧酶(IDO)在甲状腺相关性眼病(TAO)中的变化及其可能的作用。方法收集20例TAO患者(TAO组)和25名健康志愿者(对照组)的外周静脉血,采用流式细胞术测定外周血中IDO阳性的细胞数量、树突状细胞(DC)的数量及其IDO表达量、调节性T淋巴细胞(Treg)的数量。另取15例TAO患者(TAO组)和15例眼袋手术患者(对照组)的眶后脂肪组织,应用实时荧光定量PCR、Western印迹法检测各组眶后脂肪组织中IDO mRNA和蛋白质表达。结果 TAO组外周血中IDO阳性的细胞数量、DC的数量均显著少于对照组(P值均<0.05),DC的IDO表达量显著低于对照组(P<0.05)。TAO组外周血中Treg的数量显著少于对照组(P<0.05)。TAO组眶后脂肪组织中IDO的mRNA和蛋白质的表达量均显著低于对照组(P值均<0.05)。TAO组眶后组织中叉头状转录因子P3(FOXP3)的蛋白质表达量显著低于对照组(P<0.05)。结论 TAO患者外周血DC的数量和眶后脂肪组织的IDO表达量下降,可能通过促进T淋巴细胞增殖、抑制Treg生成参与疾病的发生、发展。

Objective To explore the expression and possible role of indoleamine 2,3-dioxygenase （IDO） in patients with thyroid associated ophthalmopathy （TAO）. Methods Peripheral venous blood samples were collected from 20 TAO patients （TAO group） and 25 healthy objects （control group）. The amounts of IDO positive cells, dendritic cells （DCs） and regulatory T cells （Tregs） and IDO expression were measured by flow cytometry. Orbital fatty tissues were collected from 15 TAO patients and 15 people undergoing lower blepharoplasty. The mRNA and protein expression of IDO in these tissues were detected by real-time PCR and Western blotting, respectively. Results Compared with the control group, the amounts of IDO positive cells, DCs and Tregs as well as the expression of IDO in DCs were significantly decreased in peripheral blood of TAO patients （all P〈0.05）. The mRNA and protein expression of IDO in the orbital adipose tissue of TAO patients and the protein expression of fork head box p3 （FOXP3） were significantly lower than those in control group （all P〈0.05）. Conclusion IDO expression in dendritic cells of peripheral blood and orbital fatty tissue is decreased in TAO patients. The downregulation of IDO expression in TAO patients may promote T cell proliferation and inhibit Treg generation in the development of the disease.