| Bisphenol A（BPA）is a kind of plasticizer,widely used in the production of A variety of daily plastic products,and widely distributes in the environment.BPA is a typical environmental estrogen,which has a similar structure to endogenous estrogen（E2）and can interfere with normal endocrine activities through estrogen receptor mediated.Studies have shown that BPA is harmful to humans and other animals.The water environment is the final collection of many pollutants,and BPA is widely present in various water bodies.Fish live in water all their lives,so the harm of BPA to fish has been widely concerned.Fatty liver is one of the main problems faced by fish culture at present.The causes of fatty liver in fish are not only nutritional factors but also environmental factors,among which environmental estrogen is one of this.Previous studies focused on the effects of BPA on fish reproduction and development,but paid little attention to the effects of BPA on lipid metabolism in fish.Therefore,how BPA affects fish liver lipid metabolism and how to improve the lipid metabolism caused by BPA remains to be explored.So this study uses Gobiocypris rarus rare minnow,to explore the effect of BPA on liver lipid metabolism of rare minnow,and provide conclusive evidence for risk evaluation of BPA and aquaculture waters protection.At the same tme,through added in the feed at the same time have promoting effect of lipid metabolism for the material,to find the corresponding improvement measures,provide a reference for fish protection and health care.To investigate the effects of BPA on lipid metabolism of rare minnow,5-month-old male rare minnows were respectively exposed to 15 μg/L BPA for 1,3 and 5 week.Use Paraffin section was used to observe the effect of BPA on liver histology of rare minnow;Frozen section and oil red O staining were used to observe the neutral lipid deposition of BPA in liver;Lipidome detection was used to detect the changes of lipid content in liver of minows minows;Real-time fluorescence quantitative PCR was used to detecte the expression levels of lipid metabolization-related genes pgk1,gpd1a,tpi1,gpat3,gpat4,dgat1a,dgat1b,apoB100,apoCⅠ,apoCⅡ and apoE in liver.The main results of the study are as follows:1.After BPA exposure,liver weight increased observably,HSI increased observably,intercellular gaps widened,and accumulation of neutral lipids in liver increased.Meanwhile,after 5 weeks of BPA exposure,the content of DG in liver of rare minnow was significantly decreased,while the content of TG was significantly increased.This suggests that BPA can indeed induce fatty liver in rare minnow.2.After 5 weeks of BPA exposure,the expressions of genes related to TG lipidolysis（pgk1,gpd1a,and tpil）in liver of rare minnow were significantly decreased,while the expressions of genes related to TG synthesis（gpat3,gpat4,dgat1a and dgat1b）were significantly increased.These results suggest that BPA can affect liver lipid metabolism in rare minnow by regulating genes related to TG lipidolysis and synthesis.At the same time,BPA also affected the expression of genes related to TG transport（apoB100,apoCⅠ,apoCⅡ and apoE）to varying degrees.It suggests that BPA can affect lipid metabolism through multiple pathways.On the other hand,we fed a diet supplemented with 0.01%of resveratrol,0.05%of bile acid,0.01%of allicin,0.1%of betaine,and 0.01%of inositol to rare minnows exposed to 15μg/L BPA for 5 weeks.The contents of DG and TG in liver of rare minnow were detected using DG and TG kits.The expression levels of pgk1,gpd1a,tpi1,gpat3,gpat4,dgat1a,dgat1b,apoB100,apoCⅠ,apoCⅡ and apoE genes in liver were detected by real-time fluorescence quantitative PCR.The results of the study are shown as follows:1.In the treatment group fed with resveratrol,bile acid and inositol diet,the contents of TG and DG in liver of rare minnow were restored to normal levels.In allicin group,TG content returned to normal level,but DG content was still lower than normal level.But still TG betaine group is significantly higher than the control group,DG were significantly lower than the control group.This indicates that in this reserarch,resveratrol,bile acid,allicin and inositol all have certain improvement effects on liver lipid metabolism problems caused by BPA exposure,but the effect of resveratrol,bile acid and inositol is superior to that of allicin.Betaine did not have significant improvement.2.According to the expression levels of TG decomposition-related genes pgk1,gpd1a,and tpil,inositol supplementation had a better recovery effect on lipid metabolism disorder caused by BPA.According to the expression levels of TG synthesis-related genes gpat3,gpat4,dgat1a and dgat1b,bile acid and inositol supplementation had a better recovery effect on lipid metabolism disorder caused by BPA.According to the expression levels of TG transportrelated genes apoB100,apoCⅠ,apoCⅡ and apoE,dietary bile acid,allicin and inositol had better recovery effect on lipid metabolism disorder caused by BPA.Therefore,in terms of the expression of genes related to lipid metabolism,inositol,bile acid and allicin have better effects than resveratrol and betaine.In conclusion,BPA can decrease the content of DG and increase the content of TG in liver of rare minnow.Meanwhile,resveratrol,bile acid,allicin and inositol could improve liver lipid metabolism disorders caused by BPA exposure in rare minnow to a certain extent.But,by contrast,the improvement from high to low is respectively inositol,bile acid,resveratrol,and allicin.Betaine had no significant effect on liver TG accumulation induced by BPA in rare minnow. |
