Alleviative Effect Of Selenium On Lead-induced Oxidative Stress And Immune Toxicity In Chicken Hearts

Lead?Pb?is a toxic heavy metal,which can harm human and animal health.Selenium?Se?is one of the essential trace elements in humans and animals,and can alleviate the toxic effects of heavy metals.There have been studies on animal lead poisoning at home and abroad,but the mechanism of selenium alleviating the lead-induced oxidative stress and immune toxicity in chicken hearts is not clear.Therefore,this study established a Pb-Se model for chickens.By observing the microstructure and ultrastructure of chicken hearts,and detecting the levels of oxidative stress factors,NO,iNOS,cytokine,and heat shock protein,we explored the mechanism of selenium alleviating lead-induced oxidative stress and immune toxicity in chicken hearts.At 7days of age,180 Hyline male chickens were randomly divided into the control group,Se group,Pb+Se group,and Pb group,each group of 45 chickens.The control group was fed with a standard commercial diet?containing 0.49 mg/kg Se?and drinking water;The Se group was fed with sodium selenite added to the standard commercial diet?containing 1 mg/kg Se?and drinking water;The Pb+Se group was fed with sodium selenite added to the standard commercial diet?containing1 mg/kg Se?and lead acetate added to drinking water?containing 350 mg/L Pb?;The Pb group was fed with the standard commercial diet and lead acetate added to drinking water?containing 350mg/L Pb?.On the 30^th,60^th,and 90^th days of the experiment,15 chickens were randomly selected from each group to be executed and heart tissue samples were collected.Test indicators are as follows:microstructure and ultrastructure;Oxidative stress factors?GPx,GST,and SOD activities,and GSH and MDA contents?;NO content,iNOS activity,iNOS mRNA and protein expression;mRNA expression of cytokines?IL-2,IL-4,IL-6,IL-12?,IL-17,and IFN-??and heat shock proteins?HSP27,HSP40,HSP60,HSP70,and HSP90?;and protein expression of HSP60,HSP70,and HSP90.Test results show:?1?Lead poisoning caused changes in the microstructure and ultrastructure of chicken heart tissue,and resulted in damage in chicken hearts.Selenium alleviated morphological changes and tissue damage of chicken hearts caused by lead poisoning.?2?Lead poisoning caused a decrease in GPx,GST,and SOD activities,and GSH content;and a increase in MDA content in chicken hearts,and resulted in oxidative stress in chicken hearts.Selenium alleviated the changes of the above oxidative stress factors and oxidative stress caused by lead poisoning in chicken hearts.?3?Lead poisoning increased NO content,iNOS activity,iNOS mRNA and protein expression in chicken hearts.Selenium alleviated the increase of NO and iNOS levels induced by lead poisoning in chicken hearts.?4?Lead poisoning reduced the mRNA expression of IL-2 and IFN-?in chicken hearts,and inhibited the Th1 immune response;increased IL-4,IL-6,IL-12?,and IL-17 mRNA expression,and induced Th2 immune response;Lead poisoning caused immune toxicity in chicken hearts.Selenium alleviated the changes of above cytokines and alleviated the immune toxicity in chicken hearts.?5?Lead poisoning increased the mRNA expression of HSP27,HSP40,HSP60,HSP70,and HSP90,and the protein expression of HSP60,HSP70,and HSP90 in chicken hearts.The body mobilized heat shock proteins to protect against lead poisoning.Selenium alleviated the increase in heat shock proteins expression as described above.The results showed that lead poisoning resulted in tissue damage,oxidative stress,immune toxicity,and increased heat shock proteins levels in chicken hearts.Under the condition of lead poisoning,the body launched the heat shock proteins to occur protective response.Selenium alleviated tissue damage,oxidative stress,and immune toxicity by alleviating the changes of oxidative stress factors,NO,iNOS,and cytokines in chicken hearts.