曲美他嗪对重症肺炎大鼠的肺保护作用及其机制研究

The protective effect and mechanism of trimetazidine on the lungs of rats with severe pneumonia

摘要:

目的 观察曲美他嗪（TMZ）对重症肺炎大鼠的肺保护作用，并探讨其可能机制。方法 45只SD雄性大鼠中，取35只大鼠复制重症肺炎模型，死亡5只，30只模型大鼠随机分为重症肺炎（SP）组、TMZ组、TMZ联合磷脂酸（PA）［哺乳动物雷帕霉素靶蛋白（mTOR）激活剂］组，每组10只；余10只仅注射无菌生理盐水，设为对照组。TMZ组灌胃TMZ生理盐水溶液5 mL，剂量20 mg/kg，尾静脉注射生理盐水1 mL；TMZ联合PA组灌胃TMZ生理盐水溶液5 mL，剂量20 mg/kg，尾静脉注射PA生理盐水溶液1 mL，剂量1 mg/kg；对照组、SP组分别灌胃、尾静脉注射等体积生理盐水。4组大鼠均1次/d，连续干预6 d。检测外周血辅助性T细胞17（Th17）和调节性T细胞（Treg）细胞、肺功能指标、肺泡灌洗液（BALF）中白细胞介素-1β（IL-1β）水平；采用Western blotting检测肺组织蛋白激酶B（Akt）、p-Akt、mTOR、p-mTOR蛋白的表达。结果 对照组、SP组、TMZ组、TMZ联合PA组Th17/Treg、BALF中IL-1β水平、肺容积变换量、静息通气量、肺组织p-Akt/Akt比较，经方差分析，差异有统计学意义（P <0.05）；与对照组比较，SP组外周血Th17/Treg、BALF中IL-1β水平、肺组织p-Akt/Akt升高（P <0.05），肺容积变换量、静息通气量减少（P <0.05）；与SP组比较，TMZ组外周血Th17/Treg、BALF中IL-1β水平、肺组织p-Akt/Akt降低（P <0.05），肺容积变换量、静息通气量增加（P <0.05）；与TMZ组比较，TMZ联合PA组外周血Th17/Treg降低（P <0.05），BALF中IL-1β水平、肺组织p-Akt/Akt升高（P <0.05），肺容积变换量、静息通气量减少（P <0.05）。结论 TMZ可改善重症肺炎大鼠肺功能及Th17/Treg平衡，减轻肺部炎症反应及病理变化，其作用可能通过抑制PI3K/Akt信号通路来实现。

Abstract:

Objective To observe the protective effect of trimetazidine (TMZ) on the lungs of rats with severe pneumonia (SP) and to explore its possible mechanisms.Methods A total of 45 SD male rats were used, among which 35 were taken for the establishment of SP models. Thirty rat SP models were successfully established and randomly divided into SP group, TMZ group, and TMZ combined with PA [mammalian target of rapamycin (mTOR) activator] group, each with 10 rats. The other 10 rats were injected with sterile normal saline and set as the control group. The rats in the TMZ group were gavaged with 5 mL of normal saline containing TMZ at a dose of 20 mg/kg, and were injected with 1 mL of normal saline. The rats in the TMZ combined with PA group were gavaged with 5 mL of normal saline containing TMZ at a dose of 20 mg/kg, and were injected with 1 mL of normal saline containing PA at a dose of 1 mg/kg via the tail veins. The rats in the control group and the SP group were given an equal volume of normal saline by gavage and via the tail veins, respectively. All rats were treated once a day for six days. The proportions of T helper 17 (Th17) cells and regulatory T (Treg) cells in the peripheral blood, the pulmonary function indices, and the level of interleukin-1 (IL-1β) in the bronchoalveolar lavage fluid (BALF) were detected. The protein expressions of protein kinase B (Akt), p-Akt, mTOR, and p-mTOR in lung tissues were detected by Western blotting.Results The Th17/Treg ratio, the lung volume change, resting minute ventilation, and the expression of p-Akt/Akt in the lung tissues were different among the control group, SP group, TMZ group, and TMZ combined with PA group (P < 0.05). Compared with the control group, the Th17/Treg ratio in the peripheral blood, the level of IL-1β in the BALF, and the expression of p-Akt/Akt in the lung tissues were higher, and the lung volume change and resting minute ventilation were lower in the SP group (P < 0.05). Compared with the SP group, the Th17/Treg ratio in the peripheral blood, the level of IL-1β in the BALF, and the expression of p-Akt/Akt in the lung tissues were lower, and the lung volume change and resting minute ventilation were higher in the TMZ group (P < 0.05). Compared with the TMZ group, the level of IL-1β in the BALF, and the expression of p-Akt/Akt in the lung tissues were higher, and the lung volume change and resting minute ventilation were lower in the TMZ combined with PA group (P < 0.05).Conclusions TMZ can improve the lung function and Th17/Treg balance in SP rats, and ameliorate the inflammatory response and pathological changes in the lungs, which may be achieved by inhibiting the PI3K/Akt signaling pathway.