Curcumin attenuates elastase- and cigarette smoke-induced pulmonary emphysema in mice

Curcumin, a yellow pigment obtained from turmeric (Curcumina longa), is a dietary polyphenol that has been reported to possess anti-inflammatory and antioxidant properties. The effect of curcumin against the development of pulmonary emphysema in animal models is unknown. The aim of this study was to determine whether curcumin is able to attenuate the development of pulmonary emphysema in mice. Nine-week-old male C57BL/6J mice were treated with intratracheal porcine pancreatic elastase (PPE) or exposed to mainstream cigarette smoke (CS) (60 min/day for 10 consecutive days or 5 days/wk for 12 wk) to induce pulmonary inflammation and emphysema. Curcumin (100 mg/kg) or vehicle was administrated daily by oral gavage 1 h and 24 h before intratracheal PPE treatment and daily thereafter throughout a 21-day period in PPE-exposed mice and 1 h before each CS exposure in CS-exposed mice. As a result, curcumin treatment significantly inhibited PPE-induced increase of neutrophils in bronchoalveolar lavage fluid at 6 h and on day 1 after PPE administration, with an increase in antioxidant gene expression at 6 h and significantly attenuated PPE-induced air space enlargement on day 21. It was also found that curcumin treatment significantly inhibited CS-induced increase of neutrophils and macrophages in bronchoalveolar lavage fluid after 10 consecutive days of CS exposure and significantly attenuated CS-induced air space enlargement after 12 wk of CS exposure. In conclusion, oral curcumin administration attenuated PPE- and CS-induced pulmonary inflammation and emphysema in mice.