糖皮质激素受体表达与特发性血小板减少性紫癜激素抵抗关系

Relationship between glucocorticoid receptors and glucocorticoid resistance in children with idiopathic thrombocytopenia purpura

目的通过研究原发性糖皮质激素抵抗型特发性血小板减少性紫癜(ITP)患儿糖皮质激素受体(GR)亚型GRα和GRβ表达水平,以揭示ITP糖皮质激素抵抗的可能机制。方法应用实时荧光定量-PCR法检测18例糖皮质激素敏感型、12例糖皮质激素抵抗型ITP患儿及10例正常儿童外周血单个核细胞GRα和GRβmRNA的表达水平,同时采用酶免疫分析法测定血清总皮质醇水平。结果①对照组、糖皮质激素敏感组和抵抗组3组之间GRαmRNA的表达水平差异无显著性;对照组和糖皮质激素敏感组的GRβmRNA水平差异无显著性,但糖皮质激素抵抗组的GRβmRNA水平显著高于对照组和糖皮质激素敏感组,差异有显著性(P<0.01)。②总皮质醇水平在对照组与糖皮质激素敏感组之间差异无显著性,但糖皮质激素抵抗组总皮质醇水平明显高于糖皮质激素敏感组,差异有显著性(P<0.01)。结论ITP患儿糖皮质激素抵抗可能与GRβmRNA的表达增高有关。

Objective To identify the relationship between the expression of α and β-isoforms of glucocorticoid receptors （GR） in peripheral blood mononuclear cells （PBMC） and glucocortieoid resistance in children with idiopathic thrombocytopenia purpura （ITP）. Methods Real-time PCR was used to detect the expression of GRα and GRβ mRNA in PBMC from 30 children with ITP （glucoeorticoid-sensitive, n = 18; glucocorticoid-resistant, n = 12） and 10 healthy children （ control group）. Enzyme immunoassay was used to measure plasma levels of total glucocoticoits. Results There were no significant differences in PBMC GRα mRNA levels among the glucoeorticoid-sensitive, the glucocorticoid-resistant and the control groups. Compared with the glucocorticoid-sensitive and the control groups, the expression of GRβ mRNA in the glucocorticoid-resistant group was significantly up-regulated （P〈0.01）. Plasma total glucocoticoits level in the glucocorticoid-resistant group was found to be much higher than that in the glueocorticoid-sensitive and the control groups （P 〈 0.01 ）. Conclusions The up-regulated expression of GRβ mRNA may associated with glucocorticoid resistance in children with ITP.