奥马珠单抗对支气管哮喘大鼠肺功能及气道重塑的影响及机制研究

Effects of omalizumab on pulmonary function and airway remodeling in asthmatic rats and the underlying mechanisms

摘要:

目的 探究奥马珠单抗对支气管哮喘大鼠肺功能及气道重塑的影响，并分析可能的机制。方法 将36只哮喘致敏性合格的大鼠随机分为模型组及低、中、高剂量组，每组9只，另取10只正常大鼠为对照组。除对照组外，其余各组大鼠均用卵白蛋白（OVA）致敏并雾化吸入法诱导大鼠支气管哮喘模型。其中低、中、高剂量组大鼠于模型复制成功后，分别腹腔注射83.16、166.32、332.64 mg/（kg·d）奥马珠单抗溶液，连续2周；模型组及对照组于同时间腹腔注射等量生理盐水。药物干预结束后，采用肺功能检测系统检测用力肺活量（FVC）、肺动态顺应性（Cdyn）、呼气峰值流速（PEF）；苏木精-伊红（HE）染色观察各组大鼠肺组织病理学变化并使用Image-Pro Plus 6.0图像处理软件测定气道壁内外径、平滑肌层厚度、网状基底膜厚度；Western blotting检测各组大鼠肺组织中转化生长因子β₁（TGF-β₁）、Smad同源物3（Smad3）、p-Smad3、Ⅲ型胶原蛋白（CollagenⅢ）蛋白的表达。结果 与对照组比较，模型组及低、中、高剂量组FVC、Cdyn、PEF、肺组织气道壁内外径比值降低（P <0.05），平滑肌层和基底膜层厚度增加（P <0.05），TGF-β₁、p-Smad3/Smad3、CollagenⅢ蛋白相对表达量升高（P <0.05）；与模型组比较，低、中、高剂量组FVC、Cdyn、PEF、肺组织气道壁内外径比值升高（P <0.05），平滑肌层和基底膜层厚度减少（P <0.05），TGF-β₁、p-Smad3/Smad3、CollagenⅢ蛋白相对表达量降低（P <0.05）；与低剂量组比较，中、高剂量组FVC、Cdyn、PEF、肺组织气道壁内外径比值升高（P <0.05），平滑肌层和基底膜层厚度减少（P <0.05），TGF-β₁、p-Smad3/Smad3、CollagenⅢ蛋白相对表达量降低（P <0.05）；与中剂量组比较，高剂量组FVC、Cdyn、PEF、肺组织气道壁内外径比值升高（P <0.05），平滑肌层和基底膜层厚度减少（P <0.05），TGF-β₁、p-Smad3/Smad3、CollagenⅢ蛋白相对表达量降低（P <0.05）。结论 奥马珠单抗可抑制支气管哮喘大鼠气道重塑，改善大鼠肺功能，其作用可能是通过抑制TGF-β₁/Smad3通路活化从而抑制胶原沉积实现的。

Abstract:

Objective To explore the effects of omalizumab on pulmonary function and airway remodeling in asthmatic rats, and to analyze the possible underlying mechanisms.Methods Thirty-six well-sensitized asthmatic rats were randomly divided into model group and low-dose, medium-dose and high-dose omalizumab groups, with 9 rats in each group, and 10 normal rats were set as the control group. In addition to those in the control group, the rats in the other groups were sensitized with ovalbumin (OVA) and modeled by inhalation of aerosols to induce bronchial asthma. After successful establishment of the rat models, those in the low-dose, medium-dose and high-dose omalizumab groups were intraperitoneally injected with 83.16 mg/(kg·d), 166.32 mg/(kg·d) and 332.64 mg/(kg·d) of omalizumab for 2 weeks. The rats in the model group and the control group were intraperitoneally injected with the equal volume of normal saline at the same time. After drug intervention, the forced vital capacity (FVC), dynamic lung compliance (Cdyn) and peak expiratory flow rate (PEF) were measured by pulmonary function detection system. Hematoxylin-eosin (HE) staining was used to observe the pathological changes of lung tissues of rats in each group, followed by detection of the inner and outer diameters of airway walls, thickness of the smooth muscle layer and reticular basement membrane thickness via Image Pro Plus 6.0 software. The protein expressions of transforming growth factor β₁ (TGF-β₁), mothers against decapentaplegic homolog 3 (Smad3), p-smad3, and collagen Ⅲ in lung tissues of rats in each group were determined by Western blotting.Results Compared with the control group, FVC, Cdyn, PEF and the ratio of the inner diameter to outer diameter of airway walls were decreased, the thickness of the smooth muscle layer and that of the basal membrane layer were increased, and the protein expressions of TGF-β₁, P-Smad3/Smad3 and collagen Ⅲ in lung tissues were up-regulated in the model group and the low-dose, medium-dose and high-dose omalizumab groups (P < 0.05). Compared with the model group, FVC, Cdyn, PEF and the ratio of the inner diameter to outer diameter of airway walls were higher, the thickness of the smooth muscle layer and that of the basal membrane layer were thinner, and the protein expressions of TGF-β₁, P-Smad3/Smad3 and collagen Ⅲ in lung tissues were down-regulated in the low-dose, medium-dose and high-dose omalizumab groups (P < 0.05). Compared with the low-dose omalizumab group, FVC, Cdyn, PEF and the ratio of the inner diameter to outer diameter of airway walls were increased, the thickness of the smooth muscle layer and that of the basal membrane layer were decreased, and the protein expressions of TGF-β₁, P-Smad3/Smad3 and collagen Ⅲ in lung tissues were reduced in the medium-dose and high-dose omalizumab groups (P < 0.05). Compared with the medium-dose omalizumab group, FVC, Cdyn, PEF and the ratio of the inner diameter to outer diameter of airway walls were increased, the thickness of the smooth muscle layer and that of the basal membrane layer were decreased, and the protein expressions of TGF-β₁, P-Smad3/Smad3 and collagen Ⅲ in lung tissues were down-regulated in the high-dose omalizumab group (P < 0.05).Conclusions Omalizumab can inhibit airway remodeling and improve lung function in asthmatic rats, possibly by suppressing the activation of the TGF-β₁/Smad3 pathway that further leads to the inhibition of collagen deposition.