原发性肾病综合征患儿激素冲击治疗前后白细胞介素8基因表达

Interleukin-8 gene expression before and after the pulse treatment with methylprednisolone in primary nephrotic syndrome of children

目的 观察糖皮质激素冲击治疗肾病综合征短时间内对白细胞介素 8(IL 8)在基因转录和蛋白水平的影响。方法 选择未用过或至少 3个月内未用过糖皮质激素的原发性肾病综合征患儿 30例为观察组 ,应用甲泼尼龙冲击治疗 ,分别在治疗前和冲击结束第 2天采血 ,应用ELISA法检测静脉血中IL 8的浓度 ;外周血单个核细胞 (PBMC)IL 8mRNA的表达则采用半定量逆转录聚合酶链反应的方法测定。同时设 18名健康儿童为对照组。结果 (1)甲泼尼龙冲击治疗前患儿血清IL 8含量为 2 9 5 9(7 14～ 35 2 0 8)ng/L ,治疗后为 10 80 (4 2 7～ 77 86 )ng/L ,较治疗前明显降低 (u =4 2 6 ,P <0 0 1) ;治疗前后患儿血清IL 8含量均高于正常对照组 [10 37(5 4 6～ 33 31)ng/L],差异有显著意义 (u=4 5 3、2 73,P <0 0 1)。 (2 )甲泼尼龙冲击治疗前IL 8mRNA表达为 0 86 2 (0 776～ 0 95 ) ,治疗后为 0(0～ 0 75 4 ) ,前后比较差异有显著意义 (u =3 90 2 ,P <0 0 1)。结论 肾病综合征患儿血清IL 8和PBMCIL 8mRNA表达水平均高于对照组 ,提示IL 8可能参与小儿肾病综合征的发病过程。甲泼尼龙冲击治疗后血清IL 8和PBMCIL 8mRNA表达水平均低于治疗前 ,提示甲泼尼龙冲击疗法对肾病综合征患儿IL

Objective Primary nephrotic syndrome(PNS) is one of the common renal diseases in children, the pathogenesis of which is unclear. Evidences suggested that the proteinuria of NS is associated with the increased expression of the interleukin-8 (IL-8) genes. The purpose of the study was to evaluate the serum concentration and mRNA expression of IL-8 before and after the methylprednisolone pulse therapy (MPT) in PNS.Method Thirty children with PNS diagnosed from December 2000 to October 2001 were enrolled in this study (patients group). They were not treated with glucocorticoid at least within the recent 3 months. The children aged from 1.5 to 14 years (mean 8.5 years), and included 24 boys and 6 girls. Eighteen healthy children were selected as control group after physical examination. The children in control group aged from 2 to 14 years (mean 8 years) and included 13 boys and 5 girls. All patients were treated with MPT intravenously (30 mg/kg) for successive 3 days followed by oral prednisone. The serum protein level of IL-8 was measured by ELISA according to the manufacturer′s instructions. Human IL-8 ELISA kit was purchased from Jingmei corporation Shenzhen, China. And the concentration was obtained after drawing the standard curve. The expression of IL-8 gene was detected with RT-PCR method. The important reverse transcription reagent kit and Trizol reagent were all bought from GIBCO BRL, USA. Statistical analysis of rank sum test was adopted for data processing. Results Comparison of the serum IL-8 level in the same patient before and after the therapy showed significant difference[29.59(7.14～352.08) ng/L vs. 10.80(4.27～77.86) ng/L, u=4.26,P<0.01]. The serum level in patient group before the therapy increased obviously in comparison to the level of the control group[10.37(5.46～33.31)ng/L, u=4.53 P<0.01]. The serum level of IL-8 in patient group after the therapy also showed significant difference compared to the control group (u=2.73 P<0.01). The mRNA expression of IL-8 in the same patient before and after therapy showed significant difference [0.862(0.776～0.95) vs. 0(0～0.754), u=3.902 P<0.01]. Conclusion IL-8 may be involved in the pathogenesis of PNS because of the significant increase of the serum IL-8 level and PBMC IL-8 mRNA expression in nephrotic syndrome children. Methylprednisolone pulse therapy in PNS was able to inhibit the protein production and PBMC mRNA expression of IL-8, so the therapeutic mechanism of MPT in PNS might be associated with the inhibition of IL-8 expression.