闫巍巍 章斌 朱志鹏 周红梅

[摘要] 目的 探讨Nrf2/HO-1自噬信号通路在右美托咪定抑制大鼠肺损伤的作用。 方法 SPF级健康成年雄性SD大鼠50只，采用随机数字表法将大鼠分为5组（n=10）：正常对照组、模型组（腹腔注射LPS 5 mg/kg）、右美托咪定组（造模前30 min內腹腔注射右美托咪定30 μg/kg）、Nrf2抑制剂鸦胆子苦醇组（模型制备前10 d，隔天腹腔注射鸦胆子苦醇0.4 mg/kg），鸦胆子苦醇+右美托咪定组（剂量和给药时间同前）。收集左肺支气管肺泡灌洗液，ELISA 检测中白细胞介素-1β（IL-1β），白细胞介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）水平，取右肺组织进行 HE 染色并进行肺损伤评分，计算肺组织湿重/干重（W/D）的比值，Western blot 检测肺组织中 Nrf2，HO-1，ATG-5，P62蛋白的表达。 结果 与正常对照组比较，模型组的W/D 比值，肺损伤评分， IL-1β、IL-6和TNF-α水平，Nrf2，ATG-5和P62蛋白明显增加，HO-1蛋白明显下降（P<0.05），与模型组比较，而右美托咪定组、鸦胆子苦醇组和鸦胆子苦醇+右美托咪定组明显逆转（P<0.05），且鸦胆子苦醇+右美托咪定组逆转更为明显（P<0.05）。右美托咪定组、鸦胆子苦醇组和鸦胆子苦醇+右美托咪定组明显逆转模型组大鼠肺组织损伤程度，肺间质增厚明显减少，且炎症细胞浸润程度明显减轻，其中鸦胆子苦醇+右美托咪定组大鼠改变最为明显。 结论 Nrf2/HO-1自噬信号通路参与了右美托咪定减轻大鼠肺损伤的过程。

[关键词] Nrf2/HO-1通路;右美托咪定;大鼠肺损伤;自噬;鸦胆子苦醇;炎症因子

[中图分类号] R363          [文献标识码] A          [文章编号] 1673-9701（2021）34-0031-04

[Abstract] Objective To explore the effect of Nrf2/HO-1 autophagy signaling pathway in the inhibition of lung injury in rats by dexmedetomidine（Dex）. Methods Fifty healthy adult male SD rats （SPF-grade） were selected and divided into five groups using the random number table method （n=10）. These groups were normal control group， model group （intraperitoneal injection of LPS 5 mg/kg）， Dex group （intraperitoneal injection of Dex 30 μg/kg in 30 min before modeling）， Nrf2 inhibitor brusatol group （intraperitoneal injection of brusatol 0.4 mg/kg every other day 10 d before model preparation）， brusatol+Dex group （dose and administration time as before）. Left bronchoalveolar lavage fluids were collected， in which interleukin-1β （IL-1β）， interleukin-6 （IL-6） and tumor necrosis factor-α （TNF-α） levels were detected by ELISA. Right lung tissues were obtained for HE staining and lung injury scoring， the ratios of wet weight/dry weight（W/D） of lung tissues were calculated， and the expression of Nrf2， HO-1， ATG-5， and P62 proteins in lung tissues were detected by Western blot. Results The W/D ratio， lung injury scores， IL-1β， IL-6 and TNF-α levels， Nrf2， ATG-5 and P62 proteins were significantly increased in the model group and HO-1 protein was significantly decreased than those in the normal control group（P<0.05）. However， those in Dex group， brusatol group and brusatol+Dex group were significantly reversed（P<0.05） than those in the model group， and the reversions in the brusatol+Dex group were more significantly（P<0.05）. The damage degree of lung tissue was significantly reversed and the pulmonary interstitial thickening was significantly reduced， and the degree of inflammatory cell infiltration was significantly reduced in rats of Dex group， brusatol group and brusatol+Dex group than those in the model group， with the most obvious changes in the brusatol+Dex group. Conclusion Nrf2/HO-1-autophagy signaling pathway is involved in the attenuation of lung injury by Dex in rats.

[Key words] Nrf2/HO-1 pathway; Dexmedetomidine; Lung injury in rats; Autophagy; Brusatol; Inflammatory factors

急性肺損伤是临床上常见的危重症，常由感染性休克或全身炎症反应引起，可进展为急性呼吸窘迫综合征，是导致重症患者病死的首要因素[1-2]。目前关于急性肺损伤的发病机制虽已进行不少研究，但确切的机制尚未阐明，目前国内外学者一致认同炎症级联反应在其中发挥不可或缺的作用[3]。核转录因子红细胞系 2p45 相关因子2（Nrf2）是一种重要的机体内保护性转录因子[4]，活化后可由细胞质转至核内，诱导下游抗氧化及抗炎分子如血红素加氧酶-1（HO-1）上调[5]，近年来随着对Nrf2/HO-1通路的深入了解，Nrf2/HO-1通路还参与自噬调节，通过影响机体自噬过程参与生理学过程，而自噬在急性肺损伤中亦扮演作用，但Nrf2/HO-1通路调控自噬过程参与急性肺损伤的研究尚未见诸于报道[6-7]。……