The protective effects of chrysin on cadmium-induced pulmonary toxicity; a multi-biomarker approach

This study aimed to determine the potential protective effects of chrysin (CHR) on experimental cadmium (Cd)-induced lung toxicity in rats. To this end, rats were divided into five groups; Control, CHR, Cd, Cd + CHR25, Cd + CHR50. In the study, rats were treated with CHR (oral gavage, 25 mg/kg and 50 mg/kg) 30 min after giving Cd (oral gavage, 25 mg/kg) for 7 consecutive days. The effects of Cd and CHR treatments on oxidative stress, inflammatory response, ER stress, apoptosis and tissue damage in rat lung tissues were determined by biochemical and histological methods. Our results revealed that CHR therapy for Cd-administered rats could significantly reduce MDA levels in lung tissue while significantly increasing the activity of antioxidant enzymes (SOD, CAT, GPx) and GSH levels. CHR agent exerted antiinflammatory effect by lowering elevated levels of NF-& kappa;B, IL-1 & beta; IL-6, TNF-& alpha;, RAGE and NRLP3 in Cd-induced lung tissue. Moreover CHR down-regulated Cd-induced ER stress markers (PERK, IRE1, ATF6, CHOP, and GRP78) and apoptosis markers (Caspase-3, Bax) lung tissue. CHR up-regulated the Bcl-2 gene, an anti-apoptotic marker. Besides, CHR attenuated the side effects caused by Cd by modulating histopathological changes such as hemorrhage, inflammatory cell infiltration, thickening of the alveolar wall and collagen increase. Immunohistochemically, NF-& kappa;B and Caspase-3 expressions were intense in the Cd group, while these expressions were decreased in the Cd + CHR groups. These results suggest that CHR exhibits protective effects against Cd-induced lung toxicity in rats by ameliorating oxidative stress, inflammation, apoptosis, endoplasmic reticulum stress and histological changes.