A Study Of The Effect And Mechanism Of Selenium On Lead Poisoning In Chicken Testes

Lead（Pb）is one of the toxic heavy metals that is widely used in industry.Pb can cause environmental pollution,and accumulate in human beings and animals,affecting human and animal health.Selenium（Se）,is a necessary nutrient trace element in animals,can alleviate the toxicity effect of Pb.The aim of this study was to investigate the ameliorative effect of Se on Pb poisoning in chicken testes.Our results provided theoretical basis of an alleviative effect of Se on Pb-induced bird testis damage.One hundred eighty 1-day-old male chickens were Pre-fed for 1week and randomly divided into four groups.The control group was fed standard commercial diet（containing Se 0.49 mg/kg）and drinking water.The Se group was added sodium selenite in standard commercial diet（containing Se 1 mg/kg）and drinking water,the Pb group was fed standard commercial diet and added lead acetate（containing Pb 350 mg/L）in drinking water,the Pb/Se group was fed sodium selenite（containing Se 1 mg/kg）and drinking water（containing Pb350 mg/L）.On the 30 th,60th,and 90 th days of the experiment,15 chickens of each group were euthanized and testes were quickly removed.Glutathione peroxidase（GPx）,superoxide dismutase（SOD）,catalase（CAT）,total antioxidant capacity（T-AOC）,glutathione S-transferase（GST）,and decreased glutathione（GSH）activity;malondialdehyde（MDA）and hydrogen peroxide（H₂O₂）content;nitric oxide（NO）content and iNOS activity;Nuclear factorkappa B（NF-κB）,cyclooxygenase-2（COX-2）,tumor necrosis factor-α（TNF-α）,prostaglandin E synthases（PTGEs）,inducible nitric oxide synthase（i NOS）,inhibited interleukin（IL）-2,IL-4,IL-6,IL-12β,IL-17,and interferon-γ（IFN-γ）messenger RNA（m RNA）expression;histopathology and ultrastructural changes were determined on the 30 th,60th,and 90 th days.Pb and Se concentrations;NF-κB,iNOS,heat shock protein（HSP）60,HSP70,and HSP90 protein expression were performed on the 90 th day.The results showed as follows:（1）Pb poisoning increased Pb concentration,decreased Se concentration in testes,caused Pb accumulation;caused testis seminiferous tubules and germ cells distorted,some germ cells fell off into the lumen,and inflammatory cell infiltration appeared.Ultrastructures found that spermatocytes nucleolus disappeared,interstitial cells irregular shape,chromatin margins and mitochondrial vacuoles,caused testicular tissue damage;Se relieved all of the above Pb-induced changes,Se alleviated Pb-induced Pb accumulation and testicular damage.（2）Pb induced HSP60,HSP70,and HSP90 protein expression,Se alleviated Pb-inducedHSPs protein expression in chicken testes,the results showed that the body mobilized heat shock protein to resist Pb toxicity.（3）Pb poisoning up-regulated NF-κB,COX-2,TNF-α,PTGEs,i NOS IL-2,IL-4,IL-6,IL-12β,and IL-17 m RNA expression;NO contend and i NOS activity;NF-κB and iNOS protein expression and induced inflammation response in chicken testes;decreased IL-2 and IFN-γ mRNA expression,and caused immune suppression;Se relieved all of the above Pb-induced changes in the expression of inflammation-related factors,alleviated inflammation response and immune suppression.（4）Pb poisoning decreased SOD,GPx,CAT,T-AOC and GST activity,GSH content,increased MDA and H₂O₂ contents,and induced oxidative stress;Se alleviated all of the changes of oxidative stress induced by Pb poisoning,alleviated oxidative stress in chicken testes.