熊果酸对变应性鼻炎PM2.5暴露后氧化应激和炎性因子的影响

Effects of ursolic acid on oxidative stress and inflammatory factors in a rat model of AR after PM2.5 exposure

目的探讨熊果酸(ursolic acid,UA)对变应性鼻炎(AR)细颗粒物(particulate matter,PM2.5)吸入暴露后氧化应激和多种炎性因子的影响。方法将60只健康雌性SD大鼠随机分为5组,分别为正常对照组(NC组)、PM2.5未暴露AR组(AR组)、PM2.5暴露AR组(ARE组)、UA干预AR组(AR+UA组)和UA干预PM2.5暴露AR组(ARE+UA组),每组12只。采用卵清蛋白(OVA)腹腔注射基础致敏和滴鼻激发进行AR造模。采用吸入性暴露系统进行PM2.5吸入暴露,浓度为200μg/m3,3 h/d,连续30 d。对UA干预组采用UA灌胃,浓度为20 mg/(kg·d)。观察各组大鼠的AR症状及鼻黏膜的病理学改变。检测鼻黏膜超氧化物歧化酶(superoxide dismutase,SOD)活性及丙二醛的水平变化。酶联免疫吸附试验(ELISA)检测各组血清OVA特异性免疫球蛋白E(OVA-sIgE)、白细胞介素(IL)-6和IL-17的水平变化。蛋白芯片技术检测鼻黏膜多种炎性因子水平。采用SPSS 20.0软件,以单因素方差分析进行统计学分析。结果在UA干预后,ARE+UA组较ARE组大鼠的AR症状减轻,鼻黏膜固有层炎性细胞浸润减少,上皮层病理损伤减轻。ARE+UA组鼻黏膜SOD活性较ARE组升高[(50.10±3.09)U/mg比(20.13±1.30)U/mg,F=597.54,P<0.01],ARE+UA组鼻黏膜丙二醛含量较ARE组下降[(57.78±12.36)nmol/g比(124.12±9.40)nmol/g,F=115.51,P<0.01]。ARE+UA组血清OVA-sIgE、IL-6和IL-17水平较ARE组显著下降[(11.61±0.27)ng/ml比(20.30±0.67)ng/ml、(47.59±15.49)pg/ml比(98.83±10.98)pg/ml、(623.30±8.75)pg/ml比(913.32±9.06)pg/ml,F值分别为283.42、80.45、683.73,P值均<0.01]。蛋白芯片检测显示ARE+UA组鼻黏膜中IL-4、IL-6、IL-13、趋化因子CXCL7、IL-1α、IL-1β、基质金属蛋白酶-8和单核细胞趋化蛋白1水平较ARE组下降,而干扰素γ和IL-10的水平明显升高(P值均<0.01)。结论UA可抑制AR的氧化应激反应及炎性因子的表达和释放,对PM2.5吸入暴露诱发和加重的AR病理损伤起到保护作用。

Objective To investigate the effects of ursolic acid(UA)on oxidative stress and inflammatory factors in a rat model of AR after PM2.5 exposure.Methods Sixty healthy female SD rats were randomly divided into five groups:normal control group(NC group),PM2.5 unexposed AR group(AR group),PM2.5 exposed AR group(ARE group),UA intervention AR group(AR+UA group),and UA intervention PM2.5 exposed AR group(ARE+UA group),with 12 rats in each group.AR model was performed by a basal sensitization with intraperitoneal injection of ovalbumin(OVA)and followed by nasal instillation.PM2.5 exposure was carried out by inhalation exposure system at a concentration of 200μg/m3 for 3 h/d for 30 days.UA intervention group was given UA intragastric administration at 20 mg/(kg·d).AR symptoms including sneezing,nasal scratching and nasal secretion of rats in each group were observed.The activities of superoxide dismutase(SOD)and the level of malondialdehyde(MDA)in nasal mucosa were tested.The pathological changes of nasal mucosa were observed by HE staining.The levels of OVA-sIgE,IL-6 and IL-17 in serum were measured by enzyme-linked immunosorbent assay(ELISA).Protein microarray was used to measure the expression of multiple inflammation cell factors in nasal mucosa.Statistical analysis was performed with SPSS 20.0.Results After UA intervention,the frequency of nasal sneezing,scratching and nasal secretion in ARE+UA group were lower than those of ARE group(P<0.05).Pathological examination of nasal mucosa showed that ARE+UA group had less inflammatory granulocyte infiltration and less pathological damage to the epithelial layer than ARE group.The activities of SOD in nasal mucosa of ARE+UA group were higher than those of ARE group((50.10±3.09)U/mg vs(20.13±1.30)U/mg,F value was 597.54,P<0.01).The contents of MDA in nasal mucosa of ARE+UA group were lower than those of ARE group((57.78±12.36)nmol/g vs(124.12±9.40)nmol/g,F value was 115.51,P<0.01).The expression levels of OVA-sIgE,IL-6 and IL-17 proteins were lower in the ARE+UA group than those in ARE group((11.61±0.27)ng/ml vs(20.30±0.67)ng/ml,(47.59±15.49)pg/ml vs(98.83±10.98)pg/ml,(623.30±8.75)pg/ml vs(913.32±9.06)pg/ml,F value was 283.42,80.45,683.73,respectively,all P<0.01).After UA intervention,protein microarray analysis showed that the expression of IL-4,IL-6,IL-13,chemokine CXCL7,IL-1α,IL-1β,MMP-8 and MCP-1 in ARE+UA group was decreased compared with ARE group while IFN-γand IL-10 increased(all P<0.01).Conclusion UA can reduce the aggravated AR symptoms and pathological damage of nasal mucosa,inhibit oxidative stress and release of inflammatory factors after PM2.5 exposure,and thus plays a protective role in the pathological damage of AR induced by PM2.5 exposure.