Investigation On Selenium Content Of Corn In Heilongjiang Province And The Evaluation Of The Influence Of Necroptosis And Apoptosis Through The Oxidative Stress Pathway In The Liver Of Selenium-deficient Swine

Selenium is a highly significant micro-element which plays a crucial role in the process of growth,development and reproduction of humans as well as animals.Most areas of Heilongjiang Province are Selenium deficiency area while lack of Selenium has a strong influence on livestock and poultry breeding industry.Along with the deepening of research on the mechanism of Selenium deficiency in the body,studies on the regulation of Selenium deficiency in human disease progression have become the hot spot gradually.However,the research on mechanism of organ damage caused by Selenium deficiency in animals has rarely been reported.Studies confirmed that Selenium deficiency can cause trophic hepatic atrophy in pigs,white muscle disease and other pathological damage.Nevertheless,the Selenium content of corn in Heilongjiang Province and whether the Selenium deficiency liver injury results from necrosis and apoptosis are still not yet clear.Aiming to make sure about the condition of Selenium content in Heilongjiang Province,this experiment measures the Selenium content of 24 corn samples from eight cities in Heilongjiang Province.Attempting to identify the harm caused by Selenium deficiency to pigs,this experiment takes pig as experimental subject and divides the pigs into two parts—pigs with Selenium deficiency and control group with ordinary pigs.The experimental process sets animal model of liver injury in pigs induced by Selenium deficiency and applies H.E.staining,TUNEL staining,Quantitative Real-time PCR,Western Blot and other techniques in order to observe the morphological changes of liver and to monitor expression of apoptosis related proteins and mRNA as well as the expression of antioxidant genes and apoptotic necrotic related proteins and mRNA.The purpose of this experiment is to clarify the mechanism of liver damage caused by Selenium deficiency in pigs in order to enrich the research in mechanism of Selenium deficiency liver injury.Ultimately,brand new theoretical basis can be provided to contribute to the prevention and treatment of liver injury caused by Selenium deficiency.Results of the experiment:(1)The detection figures of the Selenium content of corn in eight cities in Heilongjiang Province were mostly about 0.003?0.005 mg/kg.Few cities had figures less than 0.003 mg/kg.It is shown from the data that Heilongjiang Province is serious Selenium deficiency area.(2)The micropathological results of this experiment showed that the liver tissue treated with Selenium deficiency diet showed liver damage,disorder or rupture of hepatocyte cord,infiltration of red blood cells and inflammatory cells in hepatic portal vein,and histological changes.At the same time,TUNEL staining showed that hepatocyte apoptosis in Selenium deficiency group was obviously much higher than that in control group,indicating that Selenium deficiency can cause inflammatory injury and apoptosis in porcine liver tissue.(3)The results showed that the activities of catalase(CAT),nitric oxide(NO)and total antioxidant capacity(T-AOC)were significantly increased(p<0.05),while the activities of OH-and total nitric oxide synthase(TNOS)were significantly decreased(p<0.05)in Selenium deficiency group.In addition,the levels of hydrogen peroxide(H2O2)and malondialdehyde(MDA)in Selenium deficiency group were apparently higher than those figures in the control group.At the same time,the body weight of pigs in the Selenium deficiency group was lower than that in the control group,which confirmed that Selenium deficiency decreased the ability of oxidative stress,immunity and antioxidation in pigs.(4)Compared with the control group,Selenium deficiency induced apoptosis in porcine liver by increasing the expression of caspase-3,caspase-9 and Bak at mRNA and protein levels and reducing the level of Bcl-2.At the same time,compared with the control group,the expression of programmed necrosis pathway-related genes mRNA and protein in Selenium deficiency group was up-regulated,which also confirmed the occurrence of programmed necrosis in Selenium-deficient pig liver.To sum up,the Selenium content of corn in Heilongjiang Province is low,and Selenium deficiency can induce apoptosis and programmed necrosis of porcine hepatocytes through oxidative stress.