| Cadmium is a kind of common environmental pollutant with wide distribution and obvious biological toxicity.Cadmium pollution can be transmitted,enriched and amplified through the food chain,which can cause osteoporosis,damage of parenchymal organs,induce tumor and other diseases.Liver is an important target organ of cadmium.Studies have shown that cadmium can lead to apoptosis of liver cells.The the main toxicological mechanism of cadmium liver toxicity is oxidative damage.Chicken is the main poultry for people’s daily consumption.Due to environmental pollution and incomplete treatment of cadmium removal with mineral additives,the potential risk of cadmium poisoning in chicken is serious,which not only affects the growth and development of chicken,but also makes cadmium enter the human body through the food chain,threatening human health.Therefore,it is urgent to find an effective way and method to detoxify chicken cadmium poisoning.Based on the toxic mechanism of oxidative damage of cadmium,the protective effects of antioxidants α-lipoic acid(β-LA)and chlorogenic acid(CGA)and their combined application on chicken liver injury were studied.Methods:96 one-week-old Yangzhou local Sanhuang chickens were randomly divided into 8 groups:control group,cadmium group,α-LA group,CGA group,α-LA+ CGA group,cadmium+β-LA group,cadmium+CGA group,cadmium+α-LA group and cadmium+α-LA+CGA group.12 chickens were in each group,half male and half female.The method of cadmium exposure was free drinking water(50 mg/L).The method of α-LA administration was mixed feeding(400 mg/kg),and the method of CGA administration was gavage(45 mg/kg).The experiment lasted for three months.The body weight,water intake and feed intake of chickens were recorded every day.After the experiment,blood samples were collected to determine the blood biochemical indexes.The liver,heart,kidney,brain and other organs were collected to calculate the organ coefficient.Liver samples were collected to observe the microscopic and ultramicro pathological changes.The activities of antioxidant enzymes GSH Px,T-SOD,CAT,GST and the contents of MDA,GSH,H2O2 and T-AOC in liver were determined by colorimetry,and the contents of Fe,Mn,Zn,Se and Cu in liver were determined by inductively coupled plasma mass spectrometry(ICP-MS).Fluorescence quantitative PCR was used to detect the expression of mitochondrial apoptosis pathway related genesResults:(1)Compared with the control group,the body weight,liver coefficient and heart coefficient of cadmium poisoning group were significantly decreased(P<0.05),while brain coefficient and kidney coefficient were significantly increased(P<0.05);There was no significant difference among the protective agent groups(P<0.05).Compared with the cadmium poisoning group,the body weight,coefficients of the protective agent and cadmium co-treatment group increased(P>0.05);Compared with α-LA+CGA+cadmium group,the body weight and organ coefficient of α-LA and CGA co-treatment group had no significant changes(P>0.05).Compared with the control group,AST,UA,CREA,cadmium in the cadmium group increased significantly or extremely significantly(P<0.05 or P<0.01),TP content and hemoglobin concentration were extremely significantly reduced(P<0.01),ALB,GLO,A/G,ALP,LDH,CK all increased to varying degrees(P>0.05);The difference between the protective agent groups was not significant(P>0.05).Compared with the cadmium group,the A/G value,ALB,and TP content of the α-LA and cadmium co-treatment group were significantly or extremely increased(P<0.05 or P<0.01),and the CREA and cadmium content were significantly decreased(P<0.05).Other indicators have no significant changes(P>0.05);The TP,ALB content in the co-treatment group of CGA and cadmium increased significantly(P<0.05).CREA,cadmium were significantly or extremely significantly decreased(P<0.05 or P<0.01).Other indicators had no significant changes(P>0.05).The A/G value and TP,ALB content of the co-treatment group α-LA+CGA+cadmium significantly or extremely significantly increased(P<0.05 or P<0.01).LDH,UA,CREA,cadmium content significantly or extremely significantly decreased(P<0.05 or P<0.01).Other indicators have no significant changes(P>0.05).Compared with the α-LA+CGA+cadmium group,The cadmium content in α-LA and cadmium co-treated group increased significantly(P<0.05);CGA and cadmium co-treatment group,each indicators had no significant changes(P>0.05).(2)The pathological changes showed that the liver of cadmium group was vacuolar degeneration,inflammatory cell infiltration,and the mitochondrial ridge breakage,fuzziness,partial dissolution of nuclear membrane and so on.Compared with the cadmium group,the damage of nucleus and mitochondria was alleviated in the group treated with α-LA and CGA.(3)The liver oxidative stress test results showed that compared with the control group,the content of MDA,GSH,H2O2 and cadmium in the cadmium group was significantly increased(P<0.01).T-SOD,GST,GSH-Px,CAT activity and T-AOC,Mn,Fe,Cu,Zn,Se content significantly or extremely significantly decreased(P<0.05 or P<0.01).There was no significant change in the indicators of each protective agent group(P>0.05).Compared with the cadmium group,the MDA,GSH,H2O2 and cadmium content of the α-LA and cadmium co-treatment group was significantly or extremely significantly reduced(P<0.05 or P<0.01),GST,GSH-Px activity and T-AOC,Mn,Cu,Zn,content were significantly or extremely significantly increased(P<0.05 or P<0.01),and other indicators had no significant changes(P>0.05).The H2O2 and cadmium content of the CGA and cadmium co-treatment group were significantly or extremely significantly reduced(P<0.05 or P<0.01).T-AOC,Mn was significantly or extremely significantly increased(P<0.05 or P<0.01),and other indicators had no significant changes(P>0.05).The content of MDA,GSH,H2O2 and cadmium in the α-LA+CGA+cadmium co-treatment group were significantly or extremely significantly reduced(P<0.05 or P<0.01),Mn,Fe,Cu,Zn,Se were significantly or extremely significantly decreased(P<0.05 or P<0.01),and other indicators had no significant changes(P>0.05).Compared with the α-LA+CGA+cadmium group,the indexes of the α-LA and cadmium co-treatment group had no significant change(P>0.05).CGA and cadmium co-treatment group MDA and H2O2 content was significantly increased(P<0.05),T-AOC and Zn significantly reduced(P<0.05),other indexes had no obvious change in the CGA and cadmium co-treatment group(P>0.05).(4)The immunohistochemical results of liver apoptotic protein Bax showed that,compared with the control group,the Bax protein expression in the cadmium group was extremely significantly increased(P<0.01).There was no significant change in each protective agent group(P>0.05).Compared with the cadmium group,the Bax protein expression of each protective agent and cadmium co-treatment group significantly or extremely significantly decreased(P<0.05).Compared with the α-LA+CGA+cadmium group,the expression of Bax protein in the α-LA and cadmium co-treatment group,and the CGA and cadmium co-treatment group was not significantly increased(P>0.05).The results of apoptosis-related gene expression showed that,compared with the control group,the expression of Bax,Cyt C,Caspase 3,and Caspase 9 in the cadmium group increased significantly or extremely significantly(P<0.05 or P<0.01).The expression of Bcl-2 and the value of Bcl-2/Bax were extremely significantly reduced(P<0.01);There was no significant difference in the expression of each gene in each protective agent group(P>0.05).Compared with the cadmium group,the expression of Bax,Cyt C,Caspase 9 and Caspase 3 in the protective agent and cadmium co-treatment group(P<0.05 or P<0.01),while the expression of Bcl-2 and Bcl-2/Bax values were significantly or extremely significantly increased(P<0.05 or P<0.01).Compared with the α-LA+CGA+cadmium group,the expression of Bcl-2 and the Bcl-2/Bax value of the α-LA and cadmium co-treatment group were significantly increased(P<0.05),while there were no significant difference in the expression of other genes(P>0.05);CGA and cadmium co-treatment group Bcl-2 expression and Bcl-2/Bax value extremely significantly decreased(P<0.01),Caspase 9 significantly increased(P<0.05).Conclusion:α-LA and CGA can reduce the accumulation of cadmium in the body,alleviate the adverse effects of cadmium poisoning on the growth and development of chickens.The combined drug effect is better.α-LA and CGA can alleviate the oxidative damage of cadmium to chicken liver,inhibit cadmium from mediating hepatocyte apoptosis through the mitochondrial pathway,and have a protective effect on cadmium-induced liver damage.Combination medication can improve chicken’s antioxidant capacity,inhibit apoptosis,and reduce the accumulation of cadmium in the body. |
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