Objective: Paraquat (PQ) is a herbicide which induces oxidative stress and inflammation. Anti-inflammatory and anti-oxidant effects were shown for Zataria multiflora (Z. multiflora) and carvacrol previously. The effects of Z. multiflora hydroalcoholic extract and carvacrol on systemic inflammation and oxidative stressinduced by inhaled PQ were examined in this study. Materials and Methods: Six groups of male rats used in this study were as follows: control group exposed to normal saline aerosol, one group exposed to PQ 54 mg/m3 aerosol, animals exposed to PQ 54 mg/m3 and treated with Z. multiflora (200 and 800 mg/kg/day) or carvacrol (20 and 80 mg/kg/day) for 16 days after the end of exposure to PQ. Exposure to PQ was performed 8 times, every other day, each time for 30 min. After the end of the treatment period, different variables were measured. Results: Significant increases in nitrite (NO2), malondialdehyde (MDA) and interleukin (IL)-6 serum levels but significant reduction of interferon-gamma (IFN-γ) serum levels as well as IFN-γ/IL-6 ratio were observed in PQ-exposed compared to control group (p<0.01 for MDA and IL-6, p<0.001 for other cases). Treatment with both doses of the extract and carvacrol specially at high dose, reduced MDA, NO2, and IL-6 but increased IFN-γ and IFN-γ/IL-6 ratio compared to un-treated PQ exposed group (p<0.05 to p<0.001). Conclusion: Treatment with Z. multiflora and carvacrol improved systemic inflammation oxidative biomarkers induced by inhaled PQ which may indicate therapeutic potential of the plant and its constituent, carvacrol in systemic inflammation and oxidative biomarkers induced by inhaled PQ.

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