| Danofloxacin mesylate(DFM)is a common animal-specific fluoroquinolone antibiotic,widely used in the treatment of animal diseases,and also used as an animal growth promoter.Fluoroquinolone have shown many adverse reactions in the clinical treatment,and a large number of studies have shown that the toxicity of fluoroquinolones is related to oxidative damage.Animal-specific fluoroquinolones such as DFM have been abused and over-dosed in usual treatment.This study investigated the possible hepatotoxicity and toxicity mechanism of DFM by studying the effects of DFM on liver tissue structure and function in mice.In this study,60 healthy mice with a body weight of about 25 g,6-7 weeks old were randomly divided into five groups: control group,negative control group,low dose group(DFM 50 mg/kg),medium dose group(DFM 200 mg/kg),high dose group(DFM 800 mg/kg),12 mice in each group,6 male and 6 female.After one week of feeding,the mice were treated by gavage,and the blood and liver tissues of the mice were collected after 35 days of continuous gavage.Through the observation of histomorphology,the determination of liver-specific enzymes in the serum,the oxidation index and lipid content in the liver,the expression of genes related to antioxidant and lipid metabolism in the liver to study the effects of DFM on the structure and function of liver tissue in mice.1.Effect of DFM on liver tissue structure in miceThe injury effect of DFM on liver tissue of mice was studied by measuring liver coefficient,determination of liver-specific enzyme activity in serum and observation of liver tissue morphology.The results are as follows:(1)Changes of liver coefficient: The liver coefficient of mice gradually increases with the increase of DFM dose.The liver coefficients of the three treatment groups were higher than the blank control group and the negative control group(P<0.05).The liver coefficients of the middle-dose group and the high-dose group were higher than those in the low-dose group.(P<0.05),there was no difference between the middle dose group and the high dose group(P>0.05).(2)Changes of liver-specific enzyme activity: The activity of glutamic pyruvic transaminase(GPT)and glutamic oxaloacetic transaminase(GOT)in the serum increased with the increase of DFM dose.The GPT and GOT activities in the three treatment groups were higher than those in the blank control group and the negative control group(P<0.05).There were differences between the low-dose group,the middle-dose group and the highdose group(P<0.05).(3)Pathological changes: The mice were found to have different degrees of swelling,hemorrhage and fat lesions,and the texture became brittle in the middle dose group and the high dose group,especially in the high dose group.After the HE staining of paraffin sections,the hepatocytes of the low-dose group showed edema,cytoplasmic swelling and interlobular hemorrhage.The middle dose group was vacuolated,the hepatocyte cytoplasm was dissolved,and the nucleus was squeezed to on one side,inflammatory cells increased;in the high-dose group,diffuse vacuolation and inflammatory cell infiltration occurred.The results showed that DFM caused damage to liver tissue in mice,and the more obvious the damage with the increase of the dose.The effect of DFM was the increase of the liver coefficient,the enzyme activity of GOT and GPT,and the pathological changes in liver tissue.Among them,high dose of DFM can cause severe fatty lesions and inflammatory cell infiltration in liver tissue structure,destroy the normal structure of liver cells,trigger the occurrence of vacuolization,and promote the increase of inflammatory cells.2.Effect of DFM on antioxidant function of liver in miceThis test analyzes the effect of DFM on the antioxidant function of liver in mice by measuring the activity of superoxide dismutase(SOD),glutathione peroxidase(GSH-Px);the content of malondialdehyde(MDA),and the determination of Sod and Gpx expression levels.The test results are as follows:(1)Changes in the activity of antioxidant enzymes: The activity of SOD and GSHPx decreased with increasing dose of DFM.The enzyme activities in the low-dose group,the middle-dose group and the high-dose group were lower than those in the blank control group and the negative control group(P<0.05).The difference between the low-dose group and the middle-dose group was not significant(P>0.05),and the difference between the middle dose group and the high dose group was significant(P<0.05).The content of MDA in the liver increased with the increase of DFM dose.The content of MDA in the three treatment groups were higher than that of the blank control group and the negative control group(P<0.05),and there were differences between the three treatment groups in the high-dose group(P<0.05).(2)Changes in antioxidant gene expression: The expression of Sod decreased with the increase of DFM dose,and the expression of Sod in the three treatment groups were lower than that of blank control group(P<0.05).There was no difference between the low-dose group and the middle-dose group(P>0.05),but the difference between the middle dose and the high dose was significant(P<0.05).The expression of Gpx increased first and then decreased with the increase of DFM dose.The expression of Gpx in the low dose group was higher than that in the blank control group(P<0.05),the middle dose group was lower than the low dose group and the blank control group(P<0.05),the high dose group was lower than the middle dose group(P <0.05).The results showed that DFM can cause oxidative damage on the liver in mice,and the damage increased with the increase of DFM dose.The effect of DFM is inhibition of antioxidant enzyme gene,reduction of antioxidant enzyme activity,and increase in peroxide production.High dose of DFM severely inhibited the expression of Sod and Gpx,decreased the activities of antioxidant enzymes SOD and GSH-Px,promoted the production of peroxide MDA,and seriously affected the antioxidant function of mouse liver.3.Effect of DFM on lipid metabolism in mouse liverThis study investigated the effect of DFM on lipid metabolism in mice liver by measuring the content of lipid and the expression levels of fat metabolism related genes: Fas,Scd1,Acox1,Apob in the liver.(1)Changes in lipid content: The content of triglyceride and cholesterol increased with the increase of DFM dose,and the content of triglyceride and cholesterol in the three treatment groups were higher than that of control groups.There was a significant difference between the low,middle and high dose groups(P<0.05).(2)The changes in the expression levels of genes:(1)The expression of Fas increased with the increase of DFM dose.The expression of Fas in the three treatment groups were higher than that in the blank control group(P<0.05).There was no difference between the middle dose group and the low dose group.(P>0.05),the high-dose group was higher than the middle-dose group and the low-dose group(P<0.05).(2)The expression of Scd1 increased and then decreased with the increase of DFM dose,and the low-dose group was higher than the control group.(P<0.05),there was no difference between the middle dose group and the blank control group(P>0.05),the high dose group was lower than the blank control group(P<0.05),and the middle dose group was lower than the low dose(P<0.05).The high dose was lower than the low dose group and the middle dose group(P<0.05).(3)The expression of Acox1 decreased with the increase of DFM dose,and the expression of Acox1 in the three treatment groups were lower than the blank control group(P<0.05),the difference between the three treatment groups was significant(P<0.05).(4)The expression of Apob decreased with the increase of DFM dose,and the three treatment groups were lower than the blank control group(P< 0.05),the difference between the three treatment groups was significant(P<0.05).The results showed that DFM could affect the lipid metabolism of liver in mice,and the influence positively correlated with the dose of DFM.The effect of DFM is that increasing the lipid content and Fas expression,inhibiting Acox1 and Apob expression,affecting fatty acid synthesis,decomposition and lipid transport in the liver. |
PDF Full Text Request