| In recent years,the liver injury of animals was frequently occurred due to the intensive farming patterns,the abuse of antibiotics and feed mycotoxins.It is urgent to develop the medicines inalleviatingliver injury of animals for the industry,because this has caused serious losses in animal husbandry,and at the same time it has also endangered human health.It was founded that Salvia miltiorrhiza polysaccharides could significantly alleviate the liver injury ofmice in ourearlier researches,but it has not been reported whether it could effectively relieve the drug-induced liver injury of chickens.In this study,Florfenicol was used to make a liver injury model to study the preventive and therapeutic effects of Salvia miltiorrhiza polysaccharides on the drug-induced liver injury of chickens.We also make a further explore on its pharmacological mechanism to provide a basis for the clinical use of Salvia miltiorrhiza polysaccharides in the prevention and treatment on drug-induced liver injury of chickens.1.Establishment of the liver injury model:One hundred and eighty1-day-old healthy chickens were randomly divided into 6 groups,that is,the drug-free control group and the five Florfenicol-treated groups.The groups were treated with Florfenicol(FFC,0.15 g/L,0.45 g/L,0.75 g/L,1.5 g/L,and 2.25 g/L)in drinking water from day 1to day 9.The chickens in each group were tested for the serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),superoxide dismutase(SOD)activity,malondialdehyde(MDA)content,glutathione(GSH)in the liver tissueand liver index at day 5,day 7,and day 9.It was advisable to determinethe optimal dose of Florfenicol which caused liver injury through the comprehensive evaluation of the above indicators.The results showed that different doses of FFC significantly increased the hepatic index(P<0.05 or P<0.01),the serum ALT and AST concentrations along with the level of MDA in liver tissue(P<0.05 or P<0.01).Moreover,it obviously reduced SOD and GSH levels in liver tissue(P<0.05 or P<0.01).In conclusion,a dosage with 1.5 g/L Florfenicol(FFC)was given to chickens for continuous 7 days to create a typical liver injury model.2.Experimental study on Salvia miltiorrhiza polysaccharides in preventing liver injury of Florfenicol in chickens.One hundred and fifty 1-day-old healthy broilers were randomly divided into 5 groups.Group A was the control group,group B was theflufenicol model group,and group C、D、E was the low(1 g/L),Medium(2 g/L),high(4 g/L)dose of SMP groups.Group B-E was added with 1.5g/L flufenicol solution in drinking water,and flufenicol solution was added per liter of water for 7 days.Group C-E was also added with the corresponding dose of SMP-in drinking water at the same time.Each group was sampled at 7,10 and 14 days of age.They were observed for the effects of liver index,liver SOD activity,GSH content,serum IL-1 and TNF-α contents.The histopathological changes in the liver were observed by HE staining.The contents of IL-1 and TNF-α in serum were detected by ELISA.The relative expression level of TAK1,IKKβ,IκBα,and NF-κB P65 mRNA were detected by RT-qPCR.The results showed that the model dose of Florfenicol model-significantly increased the liver index,serum IL-1 and TNF-α levels of chickens(P<0.01),while extremely reduced the SOD activity and GSH content in liver tissues(P<0.01).Salvia miltiorrhiza polysaccharidesat a certain dose can significantly alleviate the abnormality of the above indicators(P<0.01 or P<0.05),indicating that Salvia miltiorrhiza polysaccharides can effectively prevent liver injury caused by Florfenicol.Florfenicol can obviously increase the relative expression levels of TAK1,IKKβ and NF-κB P65 mRNA in the liver tissues of chickens(P<0.01 or P<0.05),and obviously reduce IκBα(P<0.05);And the preventive administration of Salvia miltiorrhiza polysaccharides can significantly reduce the abnormal increase of the relative expression of TAK1,IKKβ,and NF-κB P65 mRNA,improving the relative expression IκBα in the liver tissues of chickens caused by Florfenicol.3.Experimental study on Salvia miltiorrhiza polysaccharides in the treatment of liver injury of Florfenicol in chickens:One hundred and fifty 1-day-old healthy broilers were randomly divided into 5 groups.Group A was the group,group B was theflufenicol model control group,and group C-E was the low(1g/L)Medium(2 g/L)and high(4 g/L)doses of SMP groups.In the B-E groups,1.5g/L flufenicol solution was added to drinking water at day 1,and flufenicol solution was added per liter of water for 7 days.The C-E groups were drinking water from the 8th day.The corresponding doses of Salvia miltiorrhiza polysaccharide was added by the end of the experiment.Samples were taken at 15,20 and 25 days of age in each group.The SOD activity and GSH contents in the liver tissues,the levels of IL-1,TNF-α,AST and ALT in serum were detected by microplate method.The histopathological changes in the liver were observed by HE staining.The contents of IL-1 and TNF-α in serum were detected by ELISA.The relative expression levels of TAK1,IKKβ,IκBα,and NF-κB P65 mRNA were detected by RT-qPCR.The results showed that the model dose of Florfenicol model can significantly increase serum IL-1 and TNF-αlevels of chickens(P<0.01),and dramatically reduce the SOD activity and GSH content in liver tissue(P<0.01).It can markedly alleviate the abnormality of the above indicators(P<0.01 or P<0.05),after continuous treatment with a certain dose of salvia miltiorrhiza polysaccharide for 14 days,indicating that Salvia miltiorrhiza polysaccharides has an effective therapeutic effect on liver injury caused by Florfenicol in chickens.Florfenicol can significantly increase the relative expression levels of TAK1,IKKβ and NF-κB P65 mRNA in liver tissue(P<0.01 or P<0.05),and obviously reduce IκBα(P<0.05).The application of Salvia miltiorrhiza polysaccharides for 2 weeks can significantly reduce the abnormal increase of the relative expression levels of TAK1,IKKβ and NF-κB P65 mRNA,improving the relative expression IκBα in the liver tissue of chickens caused by Florfenicol.It suggests that the therapeutic mechanism of Salvia miltiorrhiza polysaccharides may be related to the regulation of liver TAK1/NF-κB P65 signaling pathway,inhibition of intense peroxidative stress response and excessive inflammatory response.Conclusion:1.5g/L Florfenicol continuous drinking for 7 days can successfully establish a liver injury model of Florfenicol in broilers;2 g/L Salvia miltiorrhiza polysaccharides is continuously added to drinking water for 2 weeks,which can effectively prevent the drug-induced liver damage in chickens.Its mechanism may be related to the regulation of TAK1/NF-κB P65 signaling pathway in the liver,thereby inhibiting intense peroxidative stress response and excessive inflammatory response. |
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