熊果酸对脂多糖诱导的小鼠急性肺损伤肺中性粒细胞活性的作用

Ursolic acid inhibits neutrophil activity in a septic mouse model induced by lipopolysaccharide

目的 探讨熊果酸 （UA）对脂多糖 （LPS）诱导小鼠炎症性急性肺损伤 （ALI）肺组织中性粒细胞的作用。方法 腹腔注射LPS （3.5mg/kg）建立小鼠ALI模型。36只健康雄性12周龄C57BL/6小鼠。随机分为：①正常对照组：单纯PBS （3.5ml/kg）腹腔注射;②LPS损伤组：先腹腔注射 LPS （3.5 mg/kg）,30 min后腹腔注射 PBS （3.5 mg/kg）;③UA 组：先腹腔注射 LPS（3.5mg/kg）,30min后腹腔注射 UA （10mg/kg）,每组12只。检测小鼠肺组织中性粒细胞髓过氧化酶活性 （MPO）,观察肺组织形态学改变,用实时定量逆转录-聚合酶链反应 （RT-PCR）法分别测定各组LPS刺激后24h小鼠肺组织肿瘤坏死因子α （TNF-α）、白介素6 （IL-6）、白介素1β（IL-1β）等炎症因子和细胞间黏附分子1 （ICAM-1）mRNA表达情况,检测肺湿/干重比 （W/D）、肺血管内皮通透性 （EBA）,并观察LPS刺激后0-96h小鼠生存时间。结果 与LPS损伤组比较,光镜下观察显示UA组肺组织中性粒细胞浸润减少,且小鼠肺组织 MPO活性在LPS刺激后24h明显降低,小鼠生存时间明显延长 （P 〈0. 05）;肺组织TNF-α、IL-6、IL-1β等炎症因子和细胞间黏附分子ICAM-1mRNA表达均降低,肺组织 W/D值和内皮通透性均明显降低 （P 〈0 .05）,且肺血管内皮损伤修复时间缩短 （P 〈0 .05）。结论 UA对LPS诱导的小鼠 ALI肺中性粒细胞活性具有一定的抑制作用,其作用机制可能通过抑制炎症因子的产生和降低肺血管内皮通透性,进而抑制炎症因子对中性粒细胞的趋化作用及其通过损伤的肺血管内皮向肺组织的迁移,最终抑制中性粒细胞的活化而减轻炎症反应,改善小鼠生存率。

Objective To assess whether ursolic acid （UA） could inhibit neutrophil activity in a septic mouse model induced by lipopolysaccharide （LPS）. Methods Thirty-three male C57BL/6 mice 12 weeks of age were used. The mice were challenged with LPS （3.5 mg/kg body weight） by intraperitoneal injection.① The animals were assigned into three groups： O The control group, which had normal PBS by intraperitoneal injection; ②LPS group, in which mice received an intraperitoneal injection of LPS; ③Ursolic acid group（UA）, which 30 minutes after the animal model was established with LPS, 10 mg/kg UA was administered. Tumor necrosis factor-α（TNF-α）, interleukin-6 （IL-6 ）, interleukin-1β（IL-1β）, intercellular cell adhesion molecule-1 （ICAM 1） mRNA expression in the lung tissue were measured by reverse transcription polymerase chain reaction （RT-PCR）. Lung histology, myeloperoxidase activity （MPO）, lung wet/dry weight ratio and lung permeability （EBA value） in lung tissues were detected.Survival time was monitored from 0-96 h after LPS treatment. Results UA markedly rescued lethality, improved survival time and lung pathological changes, inhibited TNF-α, IL-6, IL-1β and ICAM-1 expression. In addition, UA can also decrease myeloperoxidase, lung wet/dry weight ratio and lung permeability. Conclusions The results suggest that UA is capable of inhibiting neutrophil activity in septic mice induced by LPS injection through reducing pro-inflammatory cytokine production and decreasing lung permeability. UA has a potentially therapeutic role in septic shock.