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2026-07-12 PubMed

CB2 inverse agonist reverses Th1/Th2 imbalance and airway remodeling in bronchial asthma rats via TLR4/NF-κB pathway.

Effects of CB2 Receptor Inverse Agonist on Airway Remodeling and Th1/Th2 Imbalance in Bronchial Asthma Rats via TLR4/NF-κB Signaling Pathway.
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Background

Bronchial asthma (BA) is a chronic respiratory disease characterized by airway remodeling (AR) and immune dysfunction, specifically a Th1/Th2 imbalance. Current treatments often manage symptoms but struggle to fully address progressive AR, which contributes to irreversible airflow obstruction. The cannabinoid receptor 2 (CB2), primarily expressed on immune cells, is known to modulate inflammation. Investigating CB2 inverse agonists offers a novel approach to rebalance immune responses and mitigate AR by targeting underlying inflammatory pathways.

Study Design

Researchers investigated the effects of a CB2 inverse agonist in 27 male SD rats (180-220 g) divided into control (CG), model (MG), and intervention (IG) groups (n=9 each). BA was induced in MG/IG rats via ovalbumin (OVA) sensitization (100 μg OVA + 1 mg aluminum hydroxide gel, i.p. on days 1/8) followed by 1% OVA aerosol challenge (day 15, 3×/week for 8 weeks). The IG group received CB2 inverse agonist (5 mg/kg, i.p., 3×/week, 4 weeks), while CG/MG received saline. Primary endpoints included Th1/Th2 cytokine levels, Th1/Th2 cell subsets, AR parameters, and lung TLR4/NF-κB-related molecule expression.

Results

Compared to the control group, model rats (MG) exhibited significant Th1/Th2 imbalance, marked by altered cytokine profiles and cell subsets. They also showed higher airway remodeling indices, indicative of severe asthma pathology, alongside upregulated expression of TLR4 and NF-κB pathway components. Furthermore, MG rats displayed shorter asthma latency and longer attack duration during OVA challenge. Treatment with the CB2 inverse agonist in the IG group significantly ameliorated these pathological changes. > The CB2 inverse agonist reversed the Th1/Th2 imbalance and reduced airway remodeling indices compared to the model group. Mechanistically, the intervention group showed reduced protein and mRNA expression of TLR4 and NF-κB-related molecules, with the notable exception of elevated NFKBIA (an inhibitor of NF-κB), suggesting a comprehensive dampening of this inflammatory pathway.

Key Findings

  • Bronchial asthma model rats exhibited significant Th1/Th2 immune imbalance and elevated airway remodeling indices.
  • The asthma model showed upregulated TLR4 and NF-κB pathway components in lung tissue.
  • CB2 inverse agonist treatment reversed the Th1/Th2 imbalance in asthma model rats.
  • CB2 inverse agonist significantly reduced airway remodeling indices in treated animals.
  • The therapeutic effects were linked to reduced TLR4 and NF-κB expression, with elevated NFKBIA.

Why It Matters

This study highlights a novel therapeutic strategy for bronchial asthma by targeting the CB2 receptor. The findings suggest that a CB2 inverse agonist could not only mitigate the inflammatory Th1/Th2 imbalance but also actively reverse the structural changes associated with airway remodeling, a critical unmet need in chronic asthma management. This mechanism-based approach could lead to new drug development for asthma, moving beyond symptomatic relief to address underlying pathology. While this is a preclinical animal study, the clear impact on both immune balance and remodeling pathways provides a strong rationale for further investigation, potentially paving the way for human trials targeting CB2 for asthma prevention and treatment.

bronchial-asthma airway-remodeling cb2-inverse-agonist tlr4 nf-kb th1-th2-balance
Source: pubmed:42437318 · Ingested 2026-07-12 · Digest: gemini-2.5-flash