Gao Guang-Jie, Song Dan-Dan, Li Long, Zhao Fan, Sun Ying-Jie
Department of Anesthesiology, Air Force Hospital of Northern Theater Command of Chinese PLA, Shenyang 110042, China.
Department of Anesthesiology, General Hospital of Northern Theater Command of Chinese PLA, Shenyang 110016, China.
Evid Based Complement Alternat Med. 2022 Aug 18;2022:2868135. doi: 10.1155/2022/2868135. eCollection 2022.
Acute lung injury (ALI) is one of the common and severe complications of cardiopulmonary bypass (CPB), which is the primary cause of death in intensive care units. Nevertheless, there is a lack of effective treatment for ALI secondary to CPB. -Opioid receptor (KOR) agonists have been demonstrated to improve lung function after pulmonary hypertension. However, its protective role has been barely reported in CPB-induced acute respiratory distress syndrome (ARDS). Therefore, this research focused on the protective effect of a KOR agonist U50448H on ARDS and investigated its potential relationship with the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome.
Forty-five rats were randomly allocated into Sham, CPB, and U50448 groups ( = 15 rats/group). After a CPB model was successfully established in rats, CPB rats were treated with the KOR agonist U50448H. The values of extravascular lung water (EVLW), alveolar-arterial oxygen tension difference (AaDO2), and respiratory index (RI) were examined, and the lung wet/dry (/) weight ratio was also calculated. Western blot (WB) was utilized to measure the expression of MMP-9, GSDMD-C, GSDMD-N, NLRP3, ASC, pro-Caspase-1, pro-IL-1, and 7-nAChR. The immunofluorescence assay was performed for examining the expression of ROS, F480, iNOS, CD206, and 7-nAChR. Cell apoptosis was detected by the TUNEL assay. ELISA was used to test the level of LPS in serum and the level of MDA, GSH, SOD, TNF-, IL-4, IL-6, IL-18, and IL-1 in lung tissues.
It was observed that the administration of U50448H significantly reduced EVLW values and LPS levels in the lung of rats. Meanwhile, U50448H increased AaDO2 values while decreasing RI values. Moreover, the administration of U50448H alleviated the pathological damage caused by ALI secondary to CPB. U50448H repressed ROS release and oxidative stress responses, as well as lowered LPS levels in plasma and MMP-9 expression in the lung of CPB rats. Furthermore, U50448H facilitated the shift of macrophage phenotype to 2. In addition, U50448H decreased the activity of the CAP-NLRP3 inflammasome and suppressed pyroptosis in pulmonary cells.
The KOR agonist U50448H improved lung function and relieved lung injury in CPB rats, accompanied by diminished ROS and MMP-9 levels in lung tissues, promoted macrophage polarization from 1 to 2, and reduced NLRP3 inflammasome activities. These results indicated U50448H as a promising drug for the treatment of ALI secondary to CPB.
急性肺损伤（ALI）是体外循环（CPB）常见且严重的并发症之一，是重症监护病房患者死亡的主要原因。然而，对于CPB继发的ALI缺乏有效的治疗方法。κ-阿片受体（KOR）激动剂已被证明可改善肺动脉高压后的肺功能。然而，其在CPB诱导的急性呼吸窘迫综合征（ARDS）中的保护作用鲜有报道。因此，本研究聚焦于KOR激动剂U50448H对ARDS的保护作用，并探讨其与含NOD样受体家族吡咯结构域3（NLRP3）炎性小体的潜在关系。
45只大鼠随机分为假手术组、CPB组和U50448组（每组15只大鼠）。在大鼠成功建立CPB模型后，对CPB大鼠给予KOR激动剂U50448H治疗。检测血管外肺水（EVLW）、肺泡-动脉氧分压差（AaDO2）和呼吸指数（RI）值，并计算肺湿/干（W/D）重量比。采用蛋白质免疫印迹法（WB）检测基质金属蛋白酶-9（MMP-9）、Gasdermin D-C端（GSDMD-C）、Gasdermin D-N端（GSDMD-N）、NLRP3、凋亡相关斑点样蛋白（ASC）、前半胱天冬酶-1、前白细胞介素-1β（pro-IL-1β）和7-烟碱型乙酰胆碱受体（7-nAChR）的表达。进行免疫荧光分析以检测活性氧（ROS）、F4/80、诱导型一氧化氮合酶（iNOS）、CD206和7-nAChR的表达。采用末端脱氧核苷酸转移酶介导的缺口末端标记法（TUNEL）检测细胞凋亡。采用酶联免疫吸附测定法（ELISA）检测血清中脂多糖（LPS）水平以及肺组织中丙二醛（MDA）、谷胱甘肽（GSH）、超氧化物歧化酶（SOD）、肿瘤坏死因子-α（TNF-α）、白细胞介素-4（IL-4）、白细胞介素-6（IL-6）、白细胞介素-18（IL-18）和白细胞介素-1β的水平。
观察到给予U50448H可显著降低大鼠肺组织中的EVLW值和LPS水平。同时，U50448H增加AaDO2值，降低RI值。此外，给予U50448H可减轻CPB继发的ALI所致的病理损伤。U50448H抑制ROS释放和氧化应激反应，并降低CPB大鼠血浆中的LPS水平和肺组织中MMP-9的表达。此外，U50448H促进巨噬细胞表型向M2型转变。另外，U50448H降低了CAP-NLRP3炎性小体的活性，并抑制肺细胞焦亡。
KOR激动剂U50448H改善了CPB大鼠的肺功能并减轻了肺损伤，同时肺组织中ROS和MMP-9水平降低，促进巨噬细胞从M1型向M2型极化，并降低NLRP3炎性小体活性。这些结果表明U50448H有望成为治疗CPB继发ALI的药物。
