Selenium Protects against Lead-induced Apoptosis via Endoplasmic Reticulum Stress in Chicken Kidneys

Lead (Pb) is a toxic heavy metal and can harm organisms by inducing apoptosis. Selenium (Se), an essential trace element for humans and animals, can alleviate heavy metal toxicity. The aim of our study is to investigate alleviative effect of Se on Pb-induced apoptosis via endoplasmic reticulum (ER) stress in chicken kidneys. One hundred and eighty male chickens were randomly divided into four groups at 7 days of age and were fed with commercial diet (containing 0.49 mg/kg Se) and drinking water, Na₂SeO₃-added commercial diet (containing 1 mg/kg Se) and drinking water, the commercial diet and (CH₃OO)₂Pb-added drinking water (containing 350 mg/L Pb), and Na₂SeO₃-added commercial diet (containing 1 mg/kg Se) and (CH₃OO)₂Pb-added drinking water (containing 350 mg/L Pb), respectively. On the 30th, 60th, and 90th days of the experiment period, 15 chickens in each group were euthanized and the kidneys were collected. Following contents were performed: kidney ultrastructure; nitric oxide (NO) content; inducible nitric oxide synthase (iNOS) activity; relative messenger RNA (mRNA) and protein expression of iNOS, ER-related genes (glucose-regulated protein (GRP)78, GRP94, activating transcription factor (ATF)4, ATF6, and iron-responsive element (IRE)), and apoptosis-related genes (caspase-3 and B cell lymphoma-2 (Bcl-2)); and caspase-12 protein expression. The results indicated that Pb changed kidney ultrastructural structure; decreased Bcl-2 mRNA and protein expression; and increased NO content, iNOS activity, relative mRNA and protein expression of iNOS, ER-related genes, and caspase-3 and caspase-12 protein expression. Se attenuated above changes caused by Pb. Pb had time-dependent manners on NO content, GRP78, GRP94, ATF4, IRE, and caspase-3 mRNA expression. Se attenuated Pb-induced apoptosis via ER stress in the chicken kidneys.