Comparison of anti-inflammatory efficacy between dexamethasone and a standardized herbal formula, PM014, in a cigarette smoke-induced subacute mouse model of chronic obstructive pulmonary disease

Abstract

Objective: A standardized herbal formula, PM014, originated from Chungsangboha -tang, which has been used to treat various respiratory diseases, including bronchitis, asthma, and emphysema. Several previous studies have reported that the therapeutic mechanism of PM014 was mediated by an anti-inflammatory effect. Therefore, we compared anti-inflammatory efficacy between PM014 and dexamethasone (DEX) using a mouse model of cigarette smoke (CS)-induced subacute pulmonary inflammation. Materials and Methods: Female C57BL/6 mice were revealed to CS for 2 h/day, three cigarettes per day, 5 days a week for 3 weeks; the control group got no other treatment, while the DEX and PM014 groups received 1 mg/kg of DEX and 100 mg/kg of PM014, respectively (both were orally administered). The histological morphology and average alveolar size were determined by lung histology. The inflammatory cell profiles and protein expressions of pro-inflammatory cytokines including tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1 β, IL-6, and one pro-inflammatory chemokine (monocyte chemoattractant protein 1 [MCP-1]), were measured in bronchoalveolar lavage fluid (BALF). The mRNA expressions of the pro-inflammatory cytokines and chemokine were also measured in lung tissues. Results: Both PM014 and DEX attenuated histological injury and air space enlargement in lung tissue and decreased the number of inflammatory cells in BALF. Both also decreased the mRNA expressions of TNF-α, IL-6, and IL-1 β in lung tissue and reduced the protein expressions of TNF-α, IL-1 β, IL-6, and MCP-1 in BALF. Conclusion: Our results showed that the anti-inflammatory efficacy of PM014 and DEX was equivalent in a subacute mouse model of CS-induced chronic obstructive pulmonary disease.