| Objective To investigate the effects of intraperitoneal injection of thioacetamide on liver and kidney function and pathological structure of liver and kidney in rats,and to analyze the feasibility of establishing a rat model of hepatorenal syndrome by intraperitoneal injection of thioacetamide.To investigate the application value of two-dimensional shear wave elastography(2D-SWE)in noninvasive evaluation of liver and kidney fibrosis by comparing the Young’s modulus values of rat liver and kidney with pathological results.Methods 80 SD rats were divided into control group(20 rats),4-week group(20 rats),8-week group(20 rats)and 12-week group(20 rats)according to random number table method.In the control group,NS was injected intraperitoneally at a dose of 200mg/1000g,3 times a week for 4 weeks.In the 4-week group,TAA was injected intraperitoneally at a dose of 200mg/1000g,3 times a week;In the 8-week group,TAA was injected intraperitoneally at a dose of 200mg/1000g,3 times a week for 8 weeks;In the 12-week group,TAA was injected intraperitoneally at a dose of 200mg/1000g,3 times a week for 12 weeks.According to the time of modeling,at the end of the last week of modeling,the rats were placed in metabolic cages to collect urine(without drinking),and the urine volume was measured after 24 hours.The rats were weighed and anesthetized with 10%chloral hydrate(0.3 ml/100 g)according to their body weight.After abdominal skin preparation,the rats were fixed on the operating table.Young’s modulus values of rat liver and kidney were determined using 2D-SWE,and EMean,EMax and EMin parameters were obtained for each measurement.The results were measured for 5 times,and the mean value was taken.After the measurement,the rats were intraperitoneally injected with a large dose of 10%chloral hydrate,and the heart was punctured and the rats were sacrificed.Then the intact liver and kidney of the rats were immediately removed and washed with 0.9%sodium chloride solution.The right lateral,middle and triangular lobes of the liver were fixed in 10%formaldehyde solution for light microscopy,and the degree of liver fibrosis was graded according to the METAVIR score.A right kidney tissue with a length of about 20mm and a diameter of about 1mm was fixed with 2.5%glutaraldehyde for electron microscopy to evaluate the pathological changes of the kidney.The remaining kidney tissue was fixed with 10%formaldehyde for optical microscopy to evaluate the renal interstitial fibrosis area.Excel was used to establish a database for all data,and SPSS 22.0 statistical software was used.Count data were compared using the chi-square test.Measurement data were expressed as(mean±standard deviation)when normal distribution,and as median(first quartile,third quartile)when abnormal distribution.One-way analysis of variance was used to compare the liver and kidney function indexes,Young’s modulus of liver and Young’s modulus of kidney between groups,and Levene’s homogeneity of variance test was used.LSD-t method was used for pairwise comparison when the variance was equal,and Dunnett T3 method was used for pairwise comparison when the variance was unequal.Renal interstitial fiber area was compared using non-parametric test and Kruskal-Wallis H method.Liver between young’s modulus value and pathologic fibrosis stage,young’s modulus value and renal interstitial fibrosis area of correlation between the Spearman rank correlation analysis,to |r|<0.4 in linear correlation,0.4≤|r|<0.7 for moderate linear correlation,and 0.7≤|r|<1 for highly linear correlation.The receiver operating characteristic curve(ROC curve)was constructed and the area under the curve was calculated.The diagnostic threshold was determined according to the highest critical point of the Youden index(sensitivity+specificity-1).P<0.05 was considered statistically significant.Results 1.Intraperitoneal injection of thioacetamide could cause liver function damage and liver fibrosis in rats,and the constituent ratio of liver fibrosis stage in each group was statistically different(P<0.01).At 12 weeks,the liver fibrosis stage of rats entered F3-F4 stage,and on this basis,the renal function of rats was damaged.Compared with the other three groups,the renal function was significantly different(P<0.05).After 12 weeks of intraperitoneal injection of thioacetamide(200mg/kg,3 times a week),an ideal model of hepatorenal syndrome was obtained.2.According to the liver fibrosis stage,the Young’s modulus values of each group were statistically different,among which EMean and EMax had a higher correlation with liver fibrosis stage(rMean=0.89,P<0.01;rMax=0.92,P<0.01).3.Taking the pathological stage as the gold standard,the receiver operating characteristic curve was used to calculate the diagnostic efficacy of Young’s modulus parameters for fibrosis staging.EMean and EMax had high diagnostic efficacy,and the area under the curve for distinguishing each fibrosis stage was more than 0.900.The cut-off values of the Young’s modulus from F1 to F3 are very close,and the practical application value is low.4.With the increase of the degree of liver fibrosis,the area of renal fibrosis also increased gradually.The Young’s modulus of renal cortex was positively correlated with the area of renal interstitial fibrosis,and the correlation between EMean and EMax was stronger(rMean=0.81,P<0.01;rMax=0.89,P<0.01).There was no significant correlation between EMin parameters and the area of renal interstitial fibrosis(rMin=0.46,P<0.01).The correlation coefficients of creatinine,urea nitrogen and urine volume with the area of renal interstitial fibrosis were 0.219(P>0.05),0.094(P>0.05)and-0.493(P<0.01),respectively.Conclusions Intraperitoneal injection of TAA can effectively cause liver function damage and liver fibrosis in rats.At the 12th week of modeling,liver fibrosis in rats has basically entered F3-F4 stage(cirrhosis stage),and on this basis,renal insufficiency is consistent with the clinical manifestations of HRS.Therefore,intraperitoneal injection of TAA for 12 weeks can obtain an ideal rat model of HRS.2D-SWE has a high clinical application value for HRS.First,it can accurately stage liver fibrosis,even in F1 stage which is difficult to distinguish by other imaging techniques,it still has a high diagnostic efficiency.At the same time,there is a significant positive correlation between the Young’s modulus of renal cortex measured by 2D-SWE and the degree of renal fibrosis,and the increase of Young’s modulus of renal cortex can be found in the early stage of liver fibrosis,which is earlier than renal function test,which can indicate the possibility of HRS.Therefore,for patients with chronic liver disease,even if there is no abnormal renal function,renal fibrosis can be detected as early as possible through the change of Young’s modulus of renal cortex,so as to achieve early detection and early treatment and improve prognosis. |
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