Related Experiment Video
Updated: Aug 23, 2025
Improved Rodent Model of Myocardial Ischemia and Reperfusion Injury
Published on: March 7, 2022
M2 Macrophage-Derived Exosomes Regulate Myocardial Ischemia-Reperfusion And Pyroptosis Via ROS/NLRP3 Pathway
Hui Hu1, Lei Qi2, Changjie Ren3
1Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong Province, China. huhui1216@126.com.
Objective:
To evaluate whether M2 macrophage-derived exosomes protect against MI/R injury and reveal the protective mechanism of exosomes [Kourembanas 2015].
Methods:
I/R model injury was induced by temporary left anterior descending coronary artery occlusion in Sprague-Dawley (SD) rats, macrophages isolated from bone marrow-derived macrophages (BMDMs) were induced to M2 polarization, and H9C2 cells subjected to hypoxia/reperfusion (H/R) were used to establish an in vitro model. I/R-induced rats and H/R-induced H9C2 cells were treated with M2-exos in vivo and in vitro, respectively. Masson staining was performed to observe myocardial fibrosis in rats. Immunohistochemical (IHC) staining of myocardial tissues showed the expression of NLRP3 inflammasome activation and pyrolysis. Exosomes derived from IL-4-treated macrophages (M2-exos) were detected by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western bolt. Western bolt was performed to determine the protein level, including NLRP3, pro-caspase-1, cleaved caspase-1, pro-IL-1β, cleaved IL-1β, gasdermin D (GSDMD), and N-terminus of gasdermin D (GSDMD-N).
Results:
Activity of NLRP3 inflammasome and existence of pyroptosis in the rats subjected to MI/R were significantly higher than those in the control (P < 0.05). Moreover, we confirmed the accumulation of ROS during I/R injury in cardiomyocytes. M2-exos protected against I/R injury and reduced activity of NLRP3 inflammasome and existence of pyroptosis, accompanied with attenuating oxidative stress. In vitro studies showed similar effects, H9c2 cells co-cultured with M2-exos could attenuated H/R-induced cell injury, while M2-exos suppressed the expression of NLRP3 inflammasome and pyroptosis (P < 0.05).
Insights
M2 macrophage-derived exosomes protect against myocardial infarction with reperfusion (MI/R) injury by reducing NLRP3 inflammasome activation and pyroptosis. These exosomes also attenuate oxidative stress, offering a potential therapeutic strategy for heart injury.
Area of Science:
- Cardiovascular Biology
- Cellular and Molecular Medicine
- Regenerative Medicine
Background:
- Myocardial infarction with reperfusion (MI/R) injury is a significant clinical challenge.
- Inflammasome activation and pyroptosis contribute to MI/R-induced myocardial damage.
- Exosomes, particularly those derived from M2 macrophages, are emerging as potential therapeutic agents.
Purpose of the Study:
- To investigate the protective effects of M2 macrophage-derived exosomes (M2-exos) against MI/R injury.
- To elucidate the underlying protective mechanisms, focusing on the NLRP3 inflammasome pathway.
Main Methods:
- Established an in vivo rat model of MI/R and an in vitro hypoxia/reperfusion (H/R) model using H9C2 cells.
- Treated models with M2-exos and assessed myocardial fibrosis and inflammasome activation via Masson staining and immunohistochemistry.
- Characterized M2-exos using transmission electron microscopy, nanoparticle tracking analysis, and western blotting.
- Quantified protein levels related to NLRP3 inflammasome and pyroptosis.
Main Results:
- MI/R injury significantly increased NLRP3 inflammasome activity and pyroptosis in rats.
- M2-exos treatment attenuated MI/R-induced myocardial injury, reduced inflammasome activation, and decreased pyroptosis.
- Oxidative stress (ROS accumulation) was attenuated by M2-exos in both in vivo and in vitro models.
- In vitro, M2-exos protected H9C2 cells from H/R-induced injury by suppressing NLRP3 inflammasome and pyroptosis.
Conclusions:
- M2 macrophage-derived exosomes exhibit significant cardioprotective effects against MI/R injury.
- The protective mechanism involves the suppression of NLRP3 inflammasome activation and pyroptosis.
- M2-exos mitigate oxidative stress, highlighting their therapeutic potential for treating myocardial ischemia-reperfusion injury.
