Department of Anesthesiology and Perioperative Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 250012, Jinan, Shandong, China.
Department of Anesthesiology and Perioperative Medicine, Shandong Institute of Anesthesia and Respiratory Intensive Care Medicine, The First Affiliated Hospital of Shandong First Medical University, 250014, Jinan, Shandong, China.
BMC Anesthesiol. 2022 Dec 1;22(1):369. doi: 10.1186/s12871-022-01874-4.
Ventilator-induced lung injury (VILI) is caused by stretch stimulation and other factors related to mechanical ventilation (MV). NOD-like receptor protein 3 (NLRP3), an important innate immune component, is strongly associated with VILI. This study aimed to investigate the effect and mechanisms of aerobic exercise (EX) on VILI.
To test the effects of the PKC inhibitor bisindolylmaleimide I on PKC and NLRP3, male C57BL/6 mice (7 weeks old, 19 ~ 23 g) were randomly divided into four groups: control group(C), bisindolylmaleimide I-pretreated group(B), MV group, and bisindolylmaleimide I-pretreated + MV (B + MV) group. The mice were pretreated with bisindolylmaleimide I through intraperitoneal injection (0.02 mg/kg) 1 h before MV. MV was performed at a high tidal volume (30 ml/kg). To explore the ameliorative effect of EX on VILI, the mice were randomly divided into C group, MV group, EX group and EX + MV group and subjected to either MV or 5 weeks of EX training. After ventilation, haematoxylin-eosin (HE) staining and wet/dry weight ratio was used to assess lung pathophysiological changes. PKCɑ, P-PKCɑ, ASC, procaspase-1, caspase-1, pro-IL-1β, IL-1β, NLRP3 and occludin (tight junction protein) expression in lung tissues was determined by Western blotting. The level of IL-6 in alveolar lavage fluid was determined by ELISA.
NLRP3, P-PKCɑ, and PKCɑ levels were inceased in MV group, but bisindolylmaleimide I treatment reversed these changes. Inhibition of PKC production prevented NLRP3 activation. Moreover, MV increased ASC, procaspase-1, caspase-1, pro-IL-1β, and IL1β levels and decreased occludin levels, but EX alleviated these changes. HE staining and lung injury scoring confirmed an absence of obvious lung injury in C group and EX group. Lung injury was most severe in MV group but was improved in EX + MV group. Overall, these findings suggest that MV activates the NLRP3 inflammasome by activating PKCɑ and inducing occludin degradation, while Exercise attenuates NLRP3 inflammasome and PKCɑ activation. Besides, exercise improves cyclic stretch-induced degradation of occludin.
PKC activation can increase the level of NLRP3, which can lead to lung injury. Exercise can reduce lung injury by inhibiting PKCɑ and NLRP3 activation. Exercise maybe a potential measure for clinical prevention of VILI.
呼吸机相关性肺损伤（VILI）是由牵张刺激和机械通气（MV）相关的其他因素引起的。NOD 样受体蛋白 3（NLRP3）是一种重要的先天免疫成分，与 VILI 密切相关。本研究旨在探讨有氧运动（EX）对 VILI 的影响及其机制。
为了检测蛋白激酶 C（PKC）抑制剂双吲哚马来酰亚胺 I 对 PKC 和 NLRP3 的影响，将雄性 C57BL/6 小鼠（7 周龄，19~23g）随机分为四组：对照组（C）、双吲哚马来酰亚胺 I 预处理组（B）、MV 组和双吲哚马来酰亚胺 I 预处理+MV 组（B+MV）。MV 前 1h 通过腹腔注射（0.02mg/kg）对小鼠进行双吲哚马来酰亚胺 I 预处理。MV 采用大潮气量（30ml/kg）。为了探讨 EX 对 VILI 的改善作用，将小鼠随机分为 C 组、MV 组、EX 组和 EX+MV 组，并进行 MV 或 5 周 EX 训练。通气后，通过苏木精-伊红（HE）染色和湿/干重比评估肺病理生理变化。通过 Western blot 检测肺组织中 PKCα、P-PKCα、ASC、procaspase-1、caspase-1、pro-IL-1β、IL-1β、NLRP3 和 occludin（紧密连接蛋白）的表达。通过 ELISA 检测肺泡灌洗液中 IL-6 的水平。
MV 组 NLRP3、P-PKCα 和 PKCα 水平升高，但双吲哚马来酰亚胺 I 处理逆转了这些变化。PKC 的产生抑制阻止了 NLRP3 的激活。此外，MV 增加了 ASC、procaspase-1、caspase-1、pro-IL-1β 和 IL1β 水平，降低了 occludin 水平，但 EX 减轻了这些变化。HE 染色和肺损伤评分证实 C 组和 EX 组无明显肺损伤。MV 组肺损伤最严重，但在 EX+MV 组有所改善。总的来说，这些发现表明 MV 通过激活 PKCα 并诱导 occludin 降解来激活 NLRP3 炎性体，而运动则减弱 NLRP3 炎性体和 PKCα 的激活。此外，运动可改善循环拉伸诱导的 occludin 降解。
PKC 激活可增加 NLRP3 水平，从而导致肺损伤。运动通过抑制 PKCα 和 NLRP3 激活来减轻肺损伤。运动可能是临床预防 VILI 的一种潜在措施。
