内源性糖皮质激素对小鼠变应性鼻炎免疫反应的影响

摘要

Objective To study the effect of dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis on the pathogenesis of allergic rhinitis (AR) by the mouse model of decreased endogenous glucocorticoid (GC) after adrenalectomy,and further explore the mechanism of neural-endocrine regulation.Methods According to literatures,adrenalectomized (ADX) mice aud AR model were established.Eighty mice were randomly divided into four groups (n =20 per group) including control group,AR group of normal mice (AR group),AR group of bilateral ADX (bilateral ADX/AR group) and AR group of unilateral ADX (unilateral ADX/AR group).In order to assess the model of ADX,adrenal gland tissue was assayed by HE staining and the plasma adrenocorticotropic hormone (ACTH) and cortisol (CORT) concentrations were measured by enzyme-linked immunosorbent assay (ELISA).The behavioral observation,OVA-sIgE assessments and count of eosinophils/mast cells by the HE/Toluidine Blue staining of nasal septum mucosa tissue were performed to evaluate the AR model.The expression of peripheral blood CD4 + IL4 + T cells (Th2 cells) and CD4 + IFN-γ+ T cells (Th1 cells),splenocytes of CD4 + CD25 + Treg cells (Treg cells) were measured by flow cytometry to study the influence of endogenous GC on immunological indexes in different groups of mice.SPSS 16.0 software was used to analyze the data.Results The concentrations of OVA-sIgE in control group,AR group,bilateral ADX/AR group and unilateral ADX/ AR group mice were (28.86 ±3.62) ng/ml,(76.27 ± 16.47) ng/ml,(48.37 ± 8.89) ng/ml,(49.86 ± 7.19) ng/ml,respectively.There was statistically significant difference between control group and AR group (t =7.09,P ＜0.05),AR group and bilateral ADX/AR group (t =4.81,P ＜0.05),AR group and unilateral ADX/AR group (t =5.21,P ＜0.05).The level of Th2 cells in different four groups were (0.71 ±0.24)％,(7.03 ±t1.95)％,(2.44±2.06)％,(3.20 ± 1.21)％,respectively.There was statistically significant difference between control group and AR group (t =-2.93,P ＜ 0.05),AR group and bilateral ADX/AR group (t =-4.67,P ＜ 0.05),AR group and unilateral ADX/AR group (t =-3.61,P ＜ 0.05).The expression of Th2 in bilateral ADX/AR group is lower than that in unilateral ADX/AR group without significant difference (t =4.39,P ＞ 0.05).Meanwhile,the level of Th1 cells in different four groups was (0.58 ± 0.76) ％,(0.57 ± 0.59) ％,(0.72 ± 0.34) ％,(1.03 ± 0.32) ％,respectively,with no significant difference among these groups.The proportion of Treg cells was (11.10 ± 2.18)％,(4.10 ± 1.07)％,(7.15 ± 0.92)％,(4.58 ± 1.05)％,respectively,with significant difference between control and other groups (t value was-7.171,-8.273,-8.360,respectively,all P ＜ 0.05).Compared with AR group,Treg cells increased significantly in bilateral ADX/AR group (t =-2.607,P ＜ 0.05).In addition,lower expression of eosinophil and mast cell were detected in the local nasal tissue of bilateral ADX/AR group,and mast cell degranulation wasn't be observed.Conclusion Unilateral or bilateral ADX leads to HPA axis dysfunction and endogenous GC deprivation,possibly regulating the mechanism of AR through Th1/Th2 immune bias and Tregs cell'activity.%目的 通过建立肾上腺切除(adrenalectomy,ADX)小鼠模型,初步探讨下丘脑-垂体-肾上腺轴(hypothalamic-pituitary-adrenal axis,HPA轴)紊乱对小鼠变应性鼻炎(AR)发病中免疫机制的影响,进一步研究AR的神经内分泌调控机制.方法 参照文献进行ADX和AR小鼠造模,将80只ICR小鼠数字表法随机分为空白对照组、AR模型组(未切除肾上腺)、双侧ADX/AR组和单侧ADX/AR组,每组20只.苏木精-伊红(HE)染色鉴定肾上腺组织,并用酶联免疫吸附试验(ELISA)测定各组小鼠血浆促肾上腺皮质激素(adrenocorticotropic hormone,ACTH)和皮质醇(cortisol,CORT)的质量浓度以判定ADX模型.采用症状学评分、卵清蛋白特异性IgE (OVA-sIgE)含量以及鼻黏膜嗜酸粒细胞和肥大细胞计数评估AR模型.流式细胞术检测外周血CD4+ IL-4+T淋巴细胞(Th2细胞)、CD4+IFN-γ+T淋巴细胞(Th1细胞)表达率及脾脏CD4+ CD25+ Treg细胞(Treg细胞)的比例.以SPSS16.0软件进行统计学分析.结果 空白对照组、AR模型组、双侧ADX/AR组、单侧ADX/AR组小鼠OVA-sIgE的表达量分别为(28.86±3.62) ng/ml、(76.27±16.47) ng/ml、(48.37±8.89) ng/ml、(49.86±7.19)ng/ml,AR模型组显著高于其他3组,差异有统计学意义(t值分别为7.09、4.81、5.21,P值均＜0.05).各组小鼠Th2细胞表达率分别为(0.71±0.24)％、(7.03±1.95)％、(2.44±2.06)％、(3.20±1.21)％,AR模型组显著高于其他3组,差异有统计学意义(t值分别为-2.93、-4.67、-3.61,P值均＜0.05);双侧ADX/AR组较单侧ADX/AR组表达率降低,但差异无统计学意义(t=4.39,P＞0.05).各组小鼠Th1细胞表达率分别为(0.58±0.76)％、(0.57±0.59)％、(0.72±0.34)％、(1.03±0.32)％,两两组间比较差异无统计学意义.各组小鼠脾脏Treg细胞含量分别为(11.10 ±2.18)％、(4.10±1.07)％、(7.15±0.92)％、(4.58±1.05)％,与空白对照组相比,其他3组该指标均显著降低,差异有统计学意义(t值分别为-7.171,-8.273,-8.360,P值均＜0.05);与AR模型组相比,双侧ADX/AR组、单侧ADX/AR组Treg细胞比例增多,前者差异有统计学意义(t=-2.607,P＜0.05),后者差异无统计学意义(t=-1.592,P＞0.05).与AR模型组相比,双侧ADX/AR组小鼠鼻黏膜嗜酸粒细胞和肥大细胞浸润程度较轻,肥大细胞无明显脱颗粒现象.结论 单侧或双侧ADX导致HPA轴功能缺陷,可引发内源性糖皮质激素紊乱,进一步影响Th1/Th2免疫平衡以及Treg细胞反应,对AR发病有重要调控作用.