Predictive Value And Clinical Significance Of The Calcineurin Inhibitors Associated Renal Injury

Background Calcineurin inhibitors(CNI)can be used for the treatment of steroid-dependent nephrotic syndrome(SDNS)and steroid-resistant nephrotic syndrome(SRNS),its effectiveness has been recognized all the worldwide,however,with the wide application in the refractory nephrotic syndrome,we should pay more attention to the CNI associated nephrotoxicity.Cyclosporine A(Cs A)and tacrolimus(TRL,FK506)are commonly used in clinical treatment.At present,we mainly through monitoring the blood concentration and renal function to reflect the renal injury,while the renal biopsy is still the gold standard,it is is difficult to implement in clinical as which was invasive detection.Therefore,it is crucial to find biomarkers which can be highly sensitive to predict CNI associated renal injury.Objective Adriamycin nephrosis rat animal model mimicing human MCNS was constructed.We observe theb levels of the renal injury biomarkers including neutrophil gelatinase associated lipocalin(NGAL),kidney injury molecule-1(KIM-1),interleukin-18(IL-18),tumor necrosis factor alpha(TNF-?),transforming growth factor beta(TGF-?)after the treatment of the CNI in different periods,and evaluate the renal pathology in the same period as the gold standard,to find the suitable biomarkers for evaluating the CNI associated renal injury.Method 1.Adriamycin was administered as a single injection 7.5mg/kg through the tail vein of 96 Sprague-Dawley male rats.The rats were randomly divided into 2 groups: the control group and the experimental group,the control group was divided into blank control group and pred control group,the experimental group was divided into pred+Cs A group and pred+FK506 group.2.The four groups rats were given the treatment of saline,prednisone,prednisone+Cs A and prednisone+FK506 for 7 days,14 days and 21 days as the early,middle and late stages respectively.Then we collected the blood,urine and kidney tissues at the three stages.3.we collected the supernatant of the blood and urine by centrifugation,then use enzyme linked immunosorbent assay(ELISA)to detect the content of NGAL,KIM-1,IL-18,TGF-? and TGF-?.4.The morphological changes,including renal tubular injury,interstitial inflammatory cell infiltration and vascular lesions was observed by HE and PAS staning.5.T test,one-way ANOVA and Person correlation analysis were used to analysis the biomarkers and renal pathology injury by SPSS.22.0 statistical software.Result There was no obvious injury in renal pathology in early stage in each group,there was no statistically significant difference(P > 0.05).In middle stage,renal tubular injury as vacuolar degeneration of tubular epithelial cells was found in the pred control,pred+Cs A and pred+FK506 groups.The levels of u NGAL and s TGF-? level in pred+Cs A group,and the levels of s NGAL,u NGAL and u IL-18 in pred+FK506 group began to change,there were significant differences compared to pred control group(P < 0.05).The levels of s NGAL,u NGAL,s TGF-? and u IL-18 were gradually increased over time,and there was significant difference compared to 7 day group(P < 0.05).In the late stage,the renal injury was significantly aggravated in pred+Cs A and pred+FK506 groups,in addition to vacuolar degeneration of tubular epithelial cells,also found the brush off,interstitial inflammatory cell infiltration and hyaline degeneration of arteriole especially in pred+Cs A group,and the lesions was gradually expanded to the medulla.The level of TGF-? in pred+Cs A group and pred+FK506 group also began to change,there were significant differences compared to pred control group(P < 0.05).The levels of s NGAL and u NGAL in pred+Cs A group were positively correlated with the pathological score of tubulointerstitial injury(r = 0.698 and r= 0.731,P < 0.05).The pathological score of tubulointerstitial injury was more severe in the pred+Cs A group than the pred+FK506 group,and the difference was statistically significant(P<0.05).Conclusion 1.NGAL,u IL-18 and s TGF-? were the sensitive biomarkers in evaluating the CNI associated renal injury in early and middle stage,and TGF-? was the sensitive biomarkers in evaluating the CNI associated renal injury in late stage.2.The level of NGAL was positively correlated with the CNI associated renal injury.It is a sensitive and specific biomarker to evaluate the CNI associated renal injury.The urine test is worthy of clinical application as noninvasive and easy to access,especilaly for children.3.The renal injury was only found in the middle and late stage.The interstitial damage was diffuse in pred+Cs A group and focal in pred+FK506 group,the renal injury of Cs A was more serious than that of FK506.