Phytochemical-induced reduction of pulmonary inflammation during Klebsiella pneumoniae lung infection in mice

Abstract

Introduction: Curcumin, a polyphenol derived from the herb Curcuma longa, has number of antioxidant, anti-inflammatory, antimicrobial, and anti-carcinogenic activities. Its anti-inflammatory property was here studied alone and in combination with clarithromycin in a mouse model of acute inflammation. Methodology: A total of 80 mice divided into four groups were used. Mice receiving curcumin and/or clarithromycin were fed orally with curcumin (150 mg/kg/day) for 15 days prior to infection, whereas clarithromycin was administered orally (30 mg/kg/day) 12 hours post infection. Simultaneously, the control group receiving only infection but no treatment was also set up. Bacterial load estimation, histopathological examination and analysis of inflammatory parameters was performed on various days for all groups. Results: Intranasal inoculation of bacteria resulted in significant increase in neutrophil infiltration along with increased production of various inflammatory mediators (malondialdehyde, myeloperoxidase, nitric oxide, TNFα) in lung tissue. Clarithromycin treatment significantly decreased the bacterial load and other inflammatory components in infected mice, but animals receiving curcumin alone or in combination with clarithromycin showed a much more significant (p < 0.05) reduction in neutrophil influx along with reduced levels of various inflammatory parameters. Though treatment with curcumin did not reduce the bacterial load, in combination with clarithromycin, both bacterial proliferation and lung tissue damage were checked. Conclusions: Though clarithromycin, because of its associated side effects, may not be the preferred treatment, it can be used in conjunction with curcumin. The latter as an adjunct therapy will help to down regulate the exaggerated state of immune response during acute lung infection.