目的 考察黄芩苷脂质体雾化吸入对急性呼吸窘迫综合征（ARDS）小鼠肺损伤的保护作用，并探讨其机制。方法 薄膜水化法制备黄芩苷脂质体，并检测包封率、载药量、粒径、Zeta电位、分散指数、累积释放率。BALB/c小鼠随机分为对照组、模型组、黄芩苷溶液（100 mg·kg^-1，0.9%氯化钠溶液配制）组和黄芩苷脂质体低、高剂量（50、100 mg·kg^-1）组，小鼠连续3 d雾化吸入黄芩苷脂质体及黄芩苷溶液，每天1次，末次给药1 h后除对照组外各组均鼻内滴注脂多糖（LPS）构建ARDS模型。造模6 h后，取肺脏检测质量湿干比（W/D），采用苏木素-伊红（HE）和Masson染色观察肺组织病理变化，ELISA法观察支气管肺泡灌洗液（BALF）中白细胞介素-6（IL-6）、CC趋化因子配体2（CCL2）、肿瘤坏死因子-α（TNF-α）、转化生长因子-β1（TGF-β1）水平以及肺组织中丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽（GSH）水平，实时荧光定量PCR（qRT-PCR）法检测肺组织IL-6、TGF-β1、TNF-α和CCL2 mRNA表达，16S rRNA测序法观察支气管BALF菌群微生态的变化。将人正常肺上皮BEAS-2B细胞分为对照组、模型组、黄芩苷（200 μg·mL^-1）和黄芩苷脂质体低、高质量浓度（100、200 μg·mL^-1）组，除对照组外，均经LPS（250 ng·mL^-1）刺激造模，造模的同时给药，共培养72 h后，采用ELISA试剂盒检测细胞中活性氧（ROS）、线粒体膜电位（MMP）和线粒体超氧化物水平。结果 黄芩苷脂质体包封率为91.7%，载药量为25.5%，粒径为（212.300±0.424） nm，Zeta电位为（-22.4±0.9） mV，分散指数为0.517±0.052；体外释放曲线显示，黄芩苷脂质体体外释放速度显著低于黄芩苷溶液（P＜0.05）。与模型组比较，黄芩苷脂质体雾化吸入可缓解LPS造成的小鼠肺组织损伤，显著降低肺W/D（P＜0.05），显著降低BALF和肺组织中IL-6、TGF-β1、CCL2、TNF-α水平（P＜0.05），显著升高肺组织GSH、SOD水平（P＜0.05），显著降低肺组织MDA水平（P＜0.05），升高菌群厚壁菌门/拟杆菌门和菌群α多样性（P＜0.05）。与模型组比较，黄芩苷脂质体可显著缓解由LPS诱导的BEAS-2B细胞活性氧（ROS）过度表达、线粒体超氧化物水平上调以及MMP下调（P＜0.05）。且黄芩苷脂质体的上述改善作用均优于黄芩苷溶液。结论 黄芩苷脂质体雾化吸入对LPS诱导的肺损伤具有保护作用，机制与减轻细胞因子分泌过量引起的氧化损伤、线粒体功能障碍和肺部菌群失衡有关，脂质体包裹可提高黄芩苷药效。

Objective To investigate the protective effect of liposome aerosol inhalation of Baicalin on lung injury in mice with acute respiratory distress syndrome (ARDS) and explore its mechanism. Methods The liposomes of baicalein were prepared by the thin film hydration method, and the entrapment efficiency, drug loading, particle size, Zeta potential, polydispersity index and cumulative release rate were detected. BALB/c mice were randomly divided into the control group, the model group, the baicalein solution group (100 mg·kg^-1, prepared with 0.9% sodium chloride solution) and the low and high dose baicalein liposome groups (50, 100 mg·kg^-1). The mice were continuously nebulized with baicalein liposomes and baicalein solution for 3 days, once a day. One hour after the last administration, except for the control group, all groups were intranasally instilled with lipopolysaccharide (LPS) to establish the ARDS model. Six hours after modeling, the lungs were taken to detect the wet-to-dry weight ratio (W/D), and the pathological changes of lung tissue were observed by hematoxylin-eosin (HE) and Masson staining. The levels of interleukin-6 (IL-6), CC chemokine ligand 2 (CCL2), tumor necrosis factor-α (TNF-α), and transforming growth factor-β1 (TGF-β1) in bronchoalveolar lavage fluid (BALF) and the levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) in lung tissue were detected by ELISA. The mRNA expressions of IL-6, TGF-β1, TNF-α and CCL2 in lung tissue were detected by real-time fluorescence quantitative PCR (qRT-PCR), and the changes of BALF microbiota microecology were observed by 16S rRNA sequencing. BEAS-2B cells were divided into the control group, the model group, the baicalein group (200 μg·mL^-1) and the low and high concentration baicalein liposome groups (100, 200 μg·mL^-1). Except for the control group, all groups were stimulated with LPS (250 ng·mL^-1) to establish the model, and the drugs were administered simultaneously. After co-culture for 72 h, the levels of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and mitochondrial superoxide in cells were detected by ELISA kits. Results The entrapment efficiency of baicalein liposomes was 91.7%, the drug loading was 25.5%, the particle size was (212.300 ±0.424) nm, the Zeta potential was (-22.4 ±0.9) mV, and the polydispersity index was 0.517 ±0.052. The in vitro release curve showed that the in vitro release rate of baicalein liposomes was significantly lower than that of baicalein solution (P < 0.05). Compared with the model group, nebulization of baicalein liposomes could alleviate the lung tissue injury caused by LPS in mice, significantly reduce the lung W/D (P < 0.05), significantly reduce the levels of IL-6, TGF-β1, CCL2 and TNF-α in BALF and lung tissue (P < 0.05), significantly increase the levels of GSH and SOD in lung tissue (P < 0.05), significantly reduce the level of MDA in lung tissue (P < 0.05), and increase the ratio of Firmicutes to Bacteroidetes and the α diversity of the microbiota (P < 0.05). Compared with the model group, baicalein liposomes could significantly alleviate the excessive expression of ROS, the up-regulation of mitochondrial superoxide and the down-regulation of MMP induced by LPS in BEAS-2B cells (P < 0.05). Moreover, the above-mentioned improvement effects of baicalein liposomes were better than those of baicalein solution. Conclusion Liposome aerosol inhalation of baicalin have a protective effect on LPSinduced lung injury, and the mechanism is related to the reduction of oxidative damage, mitochondrial dysfunction and lung microbiota imbalance caused by excessive cytokine secretion. Liposome encapsulation can improve the efficacy of baicalein.

R285.5

天津市中医药重点领域科研项目（2022008）;全国生物技术职业教育教学指导委员会教育教学改革项目（ XMLX202452）;天津市哲学社会科学规划项目（TJJY23-004）