A Preliminary Study On DTI Imaging In Stage ? And Stage ? Diabetic Nephropathy Rats Based On The TGF-?1mRNA Expression In Renal Parenchyma

ObjetiveTo study the changes of ADC value and FA value of renal cortex and medulla and the correlation between the value of TGF-?1m RNA expression and ADC value?FA value in renal parenchyma,learning the feasibility of DTI imaging in early diagnosis of DN and the feasibility of noninvasive assessment the level of TGF-?1m RNA expression with ADC value?FA value in diabetic nephropathy of stage I and stage II using diffusion tensor imaging.So as to provide a visual,noninvasive and accurate imaging method for the early diagnosis and evaluation of therapeutic efficiency of diabetic nephropathy.Materials and Methods20 healthy male SD rats were randomly divided into diabetic group of 14 rats(DN group)and normal control of 6 rats(NC group).We injected intraperitoneally 60mg/kg streptozotocin in DN group to establish the model of diabetic nephropathy.The NC group was injected the same dose of citrate buffer in the same way.The fasting blood glucose was measured after 3 days and 24 h urine was examined for urinary microalbumin after 2 weeks.Finally,there were eight DN rats which modeled Successfully and surviving and six NC rats underwent MR scan.The scan sequences include axial T2 WI,T1WI and DTI sequence.At the end of the scan,we killed all rats immediately,and collected the blood sample to exam the serum creatinine and double kidney tissues for pathological examination.The quality of the images and the ADC value and FA value of renal parenchyma in each rat were observed by two experienced radiologists under blind method.TWO independent samples T-test was used to compare the general condition(include weight and urine volume),biochemical paremeters(include blood glucose,serum craetinine and urinary microalbumin)and TGF-?1m RNA expression between the DN group and NC group.ICC test was used to test the consistency of all the dates measured by the two doctors.The DN group and NC group renal cortex and medulla ADC values and FA values were compared by Mann-Whitney U test.The correlation between the expression of TGF-?1m RNA and FA value of renal parenchyma were tested by Pearson correlation coefficient in DN group.Results1.General situation?biochemical tests and pathological examination: There were no significant difference in body weight and blood glucose before modeling between the two groups(p>0.05).The weight was loss and the urine was significantly increased,as well as the blood glucose,in DN rats which modeled Successfully.The weight,urine and blood glucose after modeling between the two groups were statistically significant(p<0.05).The serum creatinine and urinary microalbumin were no significant difference in the two groups(p>0.05).The Pathology of all the kidney tissues in the NC group were normal.In the DN group,there were varying degrees of glomerular atrophy,renal tubular epithelial cell swelling,mesangial proliferation and glomerular basement membrane thickening.According to the degree of pathological damage and clinical and biochemical conditions,there were 5 kidneys accordance with the DN diagnostic criteria of stage I and 11 kidneys of stageII.2.The consistency of ADC values and FA values were good between the two doctors according to ICC test.3.There was no statistically significant in morphology according to T1 WI and T2 WI between the two groups.The resolution ratio of renal cortex and medulla were decreased according to ADC map and FA map in DN group.In DN group,the renal cortex and medulla ADC values were higher than those of in the NC group,and the differences were statistically significant(p<0.05).The renal cortex and medulla FA values were decreased in DN group compared with NC group,especially in the cortex.But the renal cortex and medulla FA values were no significant difference between the two groups(p>0.05).4.The expression of TGF-?1m RNA:The expression of TGF-?1m RNA was increased significantly in DN group compared with NC group.The value of TGF-?1m RNA expression was 28.703±0.330 in DN group and 28.227±0.492 in NC group,and the difference was statistically significant(p<0.05).5.The correlation between the value of TGF-?1m RNA expression and ADC value,FA value in DN group: In renal cortex and medulla,there were no significant correlation between ADC value,FA value and value TGF-?1m RNA expression value in DN group.Conclusions1.DTI is feasible for noninvasive evaluation the diabetic nephropathy of stage I and stage II.2.The ADC value of diffusion tensor imaging can find the renal function changes of diabetic nephropathy earlier than the presence of clinical urine albumin.3.In diabetic nephropathy renal cortex and medulla,the correlation between ADC value,FA value and TGF-?1m RNA expression value are unclear.