Curcumin attenuates skeletal muscle mitochondrial impairment in COPD rats: PGC-1α/SIRT3 pathway involved

•Curcumin ameliorates airway inflammation and emphysema in COPD rats.•Curcumin improves pathological changes of skeletal muscle in COPD rats.•Curcumin attenuates skeletal muscle mitochondrial damage in COPD rats.•Curcumin attenuates oxidative stress and inflammation in skeletal muscle of COPD rats.•Curcumin up-regulates the expression of PGC-1α and SIRT3 in skeletal muscle of COPD rats.

Curcumin has been widely used to treat numerous diseases due to its antioxidant property. The aim of the present study is to investigate the effect of curcumin on skeletal muscle mitochondria in chronic obstructive pulmonary disease (COPD) and its underlying mechanism. The rat model of COPD was established by cigarette smoke exposure combined with intratracheal administration of lipopolysaccharide. Airway inflammation and emphysema were notably ameliorated by the treatment with curcumin. Oral administration of curcumin significantly improved muscle fiber atrophy, myofibril disorganization, interstitial fibrosis and mitochondrial structure damage in the skeletal muscle of COPD rats. Mitochondrial enzyme activities of cytochrome c oxidase, succinate dehydrogenase, Na+/K+-ATPase and Ca2+-ATPase in skeletal muscle mitochondria from COPD rats were significantly increased after treatment with curcumin. Moreover, curcumin significantly decreased oxidative stress and inflammation by determining the levels of malondialdehyde, manganese superoxide dismutase, glutathione peroxidase, catalase, IL-6 and TNF-α in skeletal muscle of COPD rats. Furthermore, curcumin significantly increased the mRNA and protein expression of PGC-1α and SIRT3 in the skeletal muscle tissues of COPD rats. These results suggested that curcumin can attenuate skeletal muscle mitochondrial impairment in COPD rats possibly by the up-regulation of PGC-1α/SIRT3 signaling pathway.