Objective Research has shown that cerebral ischemia-reperfusion injury (CIRI) involves a series of physiological and pathological mechanisms, including inflammation, oxidative stress, and cell apoptosis. The cannabinoid receptor 2 agonist AM1241 has been found to have anti-inflammatory and anti-oxidative stress effects. However, it is unclear whether AM1241 has a protective effect against brain ischemia-reperfusion injury, and its underlying mechanisms are not yet known. Methods In this study, we investigated the anti-inflammatory, anti-oxidative stress, and anti-apoptotic effects of AM1241 and its mechanisms in BV2 cells stimulated with H 2 O 2 and in a C57BL/6 mouse model of CIRI in vitro and in vivo , respectively. Results In vitro , AM1241 significantly inhibited the release of pro-inflammatory cytokines TNF-α and IL-6, reactive oxygen species (ROS), and the increase in Toll-like receptor 4/myeloid differentiation protein 2 (MD2/TLR4) complex induced by H 2 O 2 . Under H 2 O 2 stimulation, MD2 overexpression resulted in increased levels of MD2/TLR4 complex, TNF-α, IL-6, NOX2, BAX, and Cleaved-Caspase3 (C-Caspase3), as well as the activation of the MAPK pathway and NF-κB, which were reversed by AM1241. In addition, molecular docking experiments showed that AM1241 directly interacted with MD2. Surface Plasmon Resonance (SPR) experiments further confirmed the binding of AM1241 to MD2. In vivo , AM1241 significantly attenuated neurofunctional impairment, brain edema, increased infarct volume, oxidative stress levels, and neuronal apoptosis in CIRI mice overexpressing MD2. Conclusion Our study demonstrates for the first time that AM1241 alleviates mouse CIRI by inhibiting the MD2/TLR4 complex, exerting anti-inflammatory, anti-oxidative stress and anti-apoptotic effects.
Jing-Hui Li,Xian-Feng Kuang,Xiao-Feng Zhu,He-Xiang Zhao,Jun Ma,Shi-Peng Li
Cerebral ischemia-reperfusion injury arises predominantly from excessive oxidative stress and sustained neuroinflammation. The selective cannabinoid receptor type 2 (CB2R) agonist AM1241 has shown potential to alleviate both pathological processes, yet its therapeutic efficacy is severely hampered by poor blood-brain barrier (BBB) permeability and inadequate intracerebral accumulation. To elevate the intracerebral therapeutic efficacy of AM1241, we constructed polydopamine-modified mesoporous silica nanoparticles (PMSNs) as nanocarriers to encapsulate AM1241, generating PMSNs@AM1241. Comprehensive physicochemical characterization confirmed that these nanoparticles exhibited uniform morphology, excellent dispersion, reliable storage stability, and pH-responsive drug release, enabling rapid AM1241 release in acidic environments. In vitro studies demonstrated that PMSNs@AM1241 exhibited high biocompatibility, could efficiently penetrate the blood-brain barrier, and were readily internalized by microglia. The nanomedicine effectively scavenged reactive oxygen species and suppressed neuronal apoptosis. It also inhibited the release of pro-inflammatory cytokines and reduced M1-like microglial marker expression while increasing M2-like marker expression via activation of CB2R and inhibition of the NF-κB signaling pathway, thereby exerting neuroprotective effects. In vivo, PMSNs@AM1241 significantly reduced brain edema, decreased infarct volume, attenuated histopathological damage, inhibited neuronal apoptosis, and markedly ameliorated neurological deficits in mice. Notably, the intrinsic antioxidant activity of PMSNs combined with the anti-inflammatory activity of AM1241 cooperatively modulated microglial inflammatory responses via the NF-κB signaling pathway, thereby attenuating oxidative stress and inflammatory cascades. Collectively, PMSNs@AM1241 represents an effective nanodelivery platform for cerebral ischemia-reperfusion injury, providing a novel strategy and experimental foundation.
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