Protective Effects Of Selenium And Calcium On Liver And Kidney Damage Induced By Cadmium In Mice

Due to the rapid development of industrialization and urbanization,soil heavy metal pollution is a serious problem in China.Cadmium(Cd)is an important soil heavy metal pollutant.As a toxic metal released into the environment during mining and smelting,Cd tends to accumulate in living organisms.Epidemiological studies have shown associations between chronic chronic Cd exposure and cardiovascular disease,reduced bone mineral density,and cancer.In addition,higher Cd exposure may lead to kidney damage,proximal tubular reabsorption dysfunction,and long bone fractures.Studies have been carried out to reduce Cd absorption and Cd toxicity by adding mineral nutrients.For example,adding calcium(Ca),iron(Fe)and zinc(Zn)to the feed reduced the relative bioavailability of cadmium in mice.After selenium(Se)intervention,ROS and MDA contents in rat liver and testicular cells decreased significantly,while GSH contents increased.Selenium can effectively protect organs damage and cell oxidative damage caused by Cd.However,the above studies only involved single element and did not consider the protective effect of interactions of multiple nutrient elements on adverse effects of cadmium.Based on the above background,this study first established a model of damage caused by different concentrations of Cd in mice,and determined the Cd concentration used in subsequent intervention experiments from four aspects: growth and development,liver and kidney function,oxidative stress,and histopathology.Then,independent/combined intervention experiments of Se and Ca elements were conducted to select the Se and Ca dose scheme with the best protective effect.The main research conclusions are as follows:1.Protective effect of Ca on liver and kidney damage induced by Cd in miceCompared with the single Cd group,the liver and kidney coefficients were increased with the addition of different doses of Ca,but there was no significant difference.The activity of ALT and AST in liver function and the content of BUN and Cr in renal function were both lower than those in the single Cd group,which protected the organ function injury caused by Cd.The higher the Ca dose was added,the more obvious the protective effect was,and the more normal the condition was(ALT,AST,BUN and Cr were all p<0.05 in the middle Ca+Cd group and the high Ca+Cd group compared with the single Cd group).Compared with the single Cd group,the higher the Ca dose,the more the MDA content in the viscera decreased,while the content of GSH,SOD activity,gsh-px activity and CAT activity increased,which were closer to the normal state.The addition of Ca element will protect the lesion degree of organs and tissues,and the higher the Ca dose is,the better the protective effect will be.Combined with all the indexes,100 g/kg Ca concentration had the best protective effect on liver and kidney injury.2.Protective effect of Se on liver and kidney damage induced by Cd in miceCompared with the single Cd group,the liver and kidney coefficients were significantly increased after the addition of different doses of Se(p<0.01).After joining the Se,liver function index ALT and AST activity and renal index BUN and Cr content in a separate Cd group were lower,protect viscera function damage induced by Cd,and join the Se dose,the higher the protection,the more obvious,the more normal(Se+Cd group and high Se+Cd a separate Cd group,ALT,AST,BUN and Cr four indexes(p<0.05);Compared with the single Cd group,the higher the Se dose,the more the MDA content in the viscera decreased,while the GSH content,SOD activity,gsh-px activity and CAT activity increased,which were closer to the normal state.The addition of Se element will protect the lesion degree of organs and tissues,and the higher the Se dose is,the better the protective effect will be.Overall,10 mg/kg Se concentration had the best protective effect on liver and kidney injury.3.Protective effect of Se and Ca combined intervention on liver and kidney damage induced by Cd in miceCompared with the single Cd group,the liver and kidney coefficients were significantly increased after the addition of Se and Ca at different doses(p<0.05).The activity of ALT and AST in liver function and the content of BUN and Cr in renal function in the low,medium and high Se+Ca composite group were all lower than those in the single Cd group,which protected the organ function injury caused by Cd.The higher the Se and Ca dose,the more obvious the protective effect was,and the more normal the condition was.With the increase of Se and Ca dose,the content of MDA in viscera decreased more,while the content of GSH,SOD activity and gsh-px activity increased more.However,the effect of Se and Ca on the increase of CAT activity is not a simple superposition effect.Similarly,the addition of Se and Ca elements will protect the lesion degree of organs and tissues,but the dose of Se and Ca elements is not a simple superposition effect on the protective effect.Taking all the indexes into consideration,the protective effect of 10 mg/kg Se and 100 g/kg Ca was the best.When the concentration of 1 mg/kg Se and 100 g/kg Ca was used,the protective effect on kidney injury was the best.4.Summary and comparison of optimal dosing schemesIn terms of dose combination,the protective effect of high Se+Cd group and high Se+ high Ca+Cd group was better and similar,but there were differences.The high Se+Cd group focused on the protection of liver injury,while the high Se+ high Ca+Cd group focused on the protection of kidney injury.Based on the above results,the optimal nutrient element ratio scheme was selected to provide theoretical basis and data support for the follow-up studies on nutritional intervention in cadmium-exposed populations.