Experimental Study On Real-time Shear Wave Elastrography And Contrast-enhanced Ultrasound To Evaluate The Effect Of Dietary And Drug Intervention On Non-alcoholic Fatty Liver In Rabbits

ObjectiveObserve the liver SWE and CEUS quantitative parameters,serum biochemical indexes and histopathological performances after the treatment of NAFLD rabbits by the diet and drugs（atorvastatin）.To explore the value of SWE and CEUS in evaluating the effect of dietary and drug intervention on non-alcoholic fatty liver.MethodsA total of 36 male rabbits were randomly divided into 2 groups including normal model groups（Group NM）with 12 rabbits,fatty model groups（Group FM）with 12rabbits.Group FM were fed with fatty chow for 8 weeks,Group NM were fed with normal chow for 8 weeks,and than accepting ultrasonographic.6 rabbits were selected randomly from Group FM and Group NM,Histopathological examination（HE staining、Masson staining and Electronic microscopy）were performed on liver of these rabbits to further confirmed the formation of NAFLD.The remaining 6 rabbits in the NM Group were still eatting normal chow for 4 weeks as normal control group（Group NC）.The remaining 18 rabbits in group FM were randomly divided into 3 groups including fatty control groups（Group FC）,diet intervention group（group DT）and drug intervention group（group AT）with 6 in each group.Group FC were not treated,and continue to eat fatty chow for 4 weeks.Group DT change feed types,fed with normal chow 4weeks.Group AT continue to eat fatty chow for 4 weeks,and treat with atorvastatin1.5mg/kg^-1?day^-1 meanwhile.All animals of Group NC,Group FC,Group DT and Group AT estimate for liver elastic modulus（Emean,Emin,Emax,Esd）by SWE before and after treatment（Experiment eighth and twelfth weeks）.Liver CEUS examination was performed in each group after treatments（Experiment twelfth weeks）to analyze the quantitative parameters（PI,Slope,AUC,TP,MTT,DT/2）.After radiography,10ml inferior vena cava blood was obtained from all rabbits.The liver serum function and lipid contents was detected in the laboratory.Histopathological examination（HE staining、Masson staining and Electronic microscopy）were performed on each group for assessing histopathological score or observing the ultrastructure of liver cells.The changes of liver elastic parameters before and after treatment in each group were compared.Compare the difference of elastic modulus,CEUS parameters,pathological score and serum biochemical index in each group after treatment.Results1.After fed with fatty chow for 8 weeks,all rabbits liver grayscale ultrasound showed fatty liver imaging in Group FM,and liver pathological examination in Group FM confirmed NAFLD formation.2.SWE examination results:After the dietary intervention 4 weeks,Group DT liver elastic modulus（Emean value,Emin value,Emax value）decreased significantly（P<0.05）,while no the significant differences in Esd value（P>0.05）.After treatment of atorvastatin 4 weeks,Group AT liver elastic modulus（Emean value,Emin value,Emax value,Esd value）further increased,while the differences had no significantly（P>0.05）.Without treatment 4 weeks,Group FC liver elastic modulus（Emean value,Emin value,Emax value）were increased significantly（P<0.05）,but Esd value isn’t increase significantly（P>0.05）.All the liver elastic modulus of Group NC had no significant differences between experiment eighth week and experiment twelfth week（P>0.05）.After twelve weeks of experiment,compared with Group NC,liver elastic modulus（Emean value,Emin value,Emax value,Esd value）were increased significantly（P<0.01）.Emean value,Emin value,Emax value of Group DT were lower than those of group FC（P<0.01）,while no the significant differences in Esd value（P>0.05）.All the liver elastic modulus of Group AT had no significant differences with those in Group FC（P>0.05）.Emean value,Emin value of Group AT were higher than those of group FC（P<0.01）,but other liver elastic parameters had no significant differences（P>0.05）.3.CEUS examination results:Compared with the Group NC,CEUS parameters of Group FC including PI,Slope and AUC were significantly increased,MTT,TP and DT/2were significantly shortened（P<0.01）.Compared with the Group FC,PI,Slope and AUC in Group DT were significantly increased,MTT and DT/2 in Group DT were significantly shortened,too（P<0.01）,while TP wasn’t significantly shortened（P>0.05）.Compared with the Group FC,all CEUS index of Group AT were not change significantly（P>0.05）.There were significant difference in PI,Slope,AUC and DT/2between Group AT and Group DT,however,the difference of MTT and TP between Group AT and Group DT showed no significantly.4.Histopathological examination results:Hepatic steatosis score,inflammatory activity and fibrosis stage in Group FC were notablely higher than those of Group NC（P<0.001）.Compared with the Group FC,those score in Group DT were significantly decreased（P<0.01）.Hepatic steatosis and inflammatory activity score of Group AT were not distinct with those in Group FC（P>0.05）,and there was no significant difference in fibrosis stage above two groups yet（P>0.05）.But Group DT rabbits’hepatic steatosis and inflammatory activity score,fibrosis stage is lower than those in Group AT（P<0.05）.5.Biomolecular examination results:Liver function index（ALT,AST）and blood lipid index（CHOL,TG,HDL-C,LDL-C）in Group FC increased significantly than those in Group NC（P<0.05）.Compared with biomolecular index of Group FC,plasma ALT,AST,CHOL,TG,HDL-C and LDL-C content of Group DT further deseased（P<0.05）.On the contary,liver function index and blood lipid index had no notablely distinct between Group FC and Group AT t（P>0.05）.Compared with those of Group AT,all biomolecular index of Group DT decreased significantly（P<0.05）.Conclusion1.Rabbits eating high fatty diet for 8 weeks would suffer NAFLD,and that could be detected by gray scale ultrasound.2.During a short term,the effect of simple diet intervention on NAFLD rabbits was better than that of atorvastatin alone.3.SWE enable to evaluate the effect of dietery intervention or atorvastatin treatment with NAFLD in a short term.And the quantitative parameters Emean value and Emin value can be used as good indexes for evaluating the curative effect.4.The effect of diet and atorvastatin treatment on NAFLD in the short term can be evaluated by CEUS.Quantitative parameters PI,Slope,AUC and DT/2 can be used as benifit indicators for evaluating curative effect.