Department of Pediatrics, Xijing Hospital, the Fourth Military Medical University, Xi'an, China.
Department of Geriatrics, Xijing Hospital, the Fourth Military Medical University, Xi'an, China.
Microb Pathog. 2024 Oct;195:106881. doi: 10.1016/j.micpath.2024.106881. Epub 2024 Aug 26.
The etiology of allergic rhinitis (AR) is not fully understood. Studies have shown that the maturation of children's immune systems is closely related to microecology. However, few studies have focused simultaneously on changes in respiratory and gut microbiota in AR and their correlation between microecological changes and Th1/Th2/Treg.
The aim is to investigate the pathogenesis of AR based on respiratory microecology, gut microecology, and Th1/Th2/Treg levels by applying microbiome techniques and correlation analysis.
Standardized OVA-induced AR mice were established. Serum OVA-sIgE, IL-4, IFN-γ, IL-10 were measured by ELISA, Tregs in lymph nodes were determined by flow cytometry, and the histological characteristics of nasal tissues were evaluated by Hematoxylin & Eosin (H&E). Nasal symptoms were observed to determine the reliability of the AR mouse model. Nasal lavage fluid (NALF) and fecal samples were collected after the last OVA challenge. The composition of respiratory microbiota in NALF and gut microbial in feces samples via 16S rRNA gene sequencing between the two groups, further explored the relationship between microbiota and Th1/Th2/Treg levels.
In the AR group, the incidence of nose rubbing and sneezing in each mouse was significantly increased compared with the control group (all P < 0.001) and the inflammatory cell infiltration of NALF shows a significant increase in eosinophilic and neutrophilic infiltrates upon the AR group; H&E showed that the nasal mucosa of AR mice infiltration of massive eosinophils cells and neutrophils cells. OVA-sIgE and IL-4 in the AR group were increased (P < 0.01, P < 0.05) and IFN-γ, IL-10 were significantly decreased (P < 0.01, P < 0.05). Tregs showed a downward trend in the AR group, but there was no statistical difference. Compared with the control group, the respiratory microbiota of AR mice did not change significantly, while the gut microbiota changed significantly. In gut microbiota, compared to the control group, Shannon index in the AR group revealed a significant decrease at the genus level (P < 0.01), and Simpson index was significantly increased at all levels (all P < 0.05). PCoA also showed significant differences in beta diversity between the two groups (all P < 0.05). Compared to the control group, Deferribacteres at phylum level, Roseburia, Ruminiclostridium, Anaerotruncus at genus level were significantly decreased in the AR group (all P < 0.05). Spearman's rank correlation showed that OVA-sIgE was positively correlated with Bacteroidetes, Muribaculaceae and Erysipelotrichaceae (all P < 0.05); IL-4 was significantly negatively correlated with Epsilonbacteraeota and Deferribacteres (all P < 0.05). Treg was significantly positively correlated with Patescibacteria, Lachnospiraceae, and Saccharimonadaceae in gut microecology.
Our results showed that the respiratory microbiota of AR mice was not significantly altered, but the gut microbiota varied significantly and there was a correlation between gut microbiota and Th1/Th2/Treg.
变应性鼻炎（AR）的病因尚不完全清楚。研究表明，儿童免疫系统的成熟与微生态密切相关。然而，很少有研究同时关注 AR 患者的呼吸道和肠道微生物群的变化及其与 Th1/Th2/Treg 的相关性。
通过应用微生物组技术和相关性分析，从呼吸道微生态、肠道微生态和 Th1/Th2/Treg 水平探讨 AR 的发病机制。
建立标准化 OVA 诱导的 AR 小鼠模型。通过 ELISA 法测定血清 OVA-sIgE、IL-4、IFN-γ、IL-10，采用流式细胞术测定淋巴结中的 Tregs，用苏木精和伊红（H&E）染色法评估鼻组织的组织学特征。观察鼻症状以确定 AR 小鼠模型的可靠性。在最后一次 OVA 挑战后收集鼻灌洗液（NALF）和粪便样本。通过 16S rRNA 基因测序对两组 NALF 中的呼吸道微生物群落和粪便样本中的肠道微生物群落进行分析，进一步探讨微生物群与 Th1/Th2/Treg 水平之间的关系。
在 AR 组中，与对照组相比，每只小鼠的鼻擦和打喷嚏发生率均明显增加（均 P<0.001），AR 组 NALF 中的炎症细胞浸润显示嗜酸性粒细胞和中性粒细胞浸润明显增加；H&E 显示 AR 小鼠的鼻黏膜有大量嗜酸性粒细胞和中性粒细胞浸润。AR 组 OVA-sIgE 和 IL-4 增加（P<0.01，P<0.05），IFN-γ、IL-10 明显降低（P<0.01，P<0.05）。Tregs 在 AR 组呈下降趋势，但无统计学差异。与对照组相比，AR 小鼠的呼吸道微生物群落没有明显变化，而肠道微生物群落变化明显。在肠道微生物群中，与对照组相比，AR 组的 Shannon 指数在属水平上显著降低（P<0.01），而 Simpson 指数在所有水平上均显著升高（均 P<0.05）。PCoA 也显示两组之间 beta 多样性有显著差异（均 P<0.05）。与对照组相比，AR 组的厚壁菌门水平的 Deferribacteres、Roseburia、Ruminiclostridium、Anaerotruncus 属水平显著降低（均 P<0.05）。Spearman 秩相关显示 OVA-sIgE 与拟杆菌门、Muribaculaceae 和 Erysipelotrichaceae 呈正相关（均 P<0.05）；IL-4 与 Epsilonbacteraeota 和 Deferribacteres 呈显著负相关（均 P<0.05）。Treg 与肠道微生物群中的 Patescibacteria、Lachnospiraceae 和 Saccharimonadaceae 呈显著正相关。
我们的研究结果表明，AR 小鼠的呼吸道微生物群没有明显改变，但肠道微生物群变化显著，肠道微生物群与 Th1/Th2/Treg 之间存在相关性。
