| Objective: to observe the expression of tumor necrosis factor-α (TNF-α) andnuclear factor-κB (NF-κB) in the renal tissue of rats subjected to contrast-inducednephropathy(CIN), and study the relationship among expression of TNF-α, NF-κBand tubular injury score, kidney injury molecule-1(KIM-1) expression in kidney. Theaim of this study is to explore whether there are inflammatory response mechanism inthe pathogenesis of CIN.Methods: Ninety-six adult male Sprague-Dawley rats with mean of weight(300±50)g were randomly divided into two groups.They were control group(n=48),CIN group(n=48). To develop the model of contrast induced nephropathy, rats of CINgroup were injected iodinated contrast media (76%compound diatrizoateinjection,10ml/kg) by rat tail vein, while rats of control group were given sameamount of saline. Six rats of each group were sacrificed at6h,12h,24h,48h,72h,5d,10d,15d respectively after intravenous injection, and sample of rat blood and kidneywere obtained. Serum creatinine(Scr) and urea nitrogen(BUN) were measured. Someof renal tissue was stored for RNA extraction, other renal tissue was embedded inparaffin and sliced routinely. The histopathologic degrees of renal tubular cell injurywere scored in HE-stained sections. The protein and mRNA expressions of KIM-1,TNF-α, NF-κB in renal tissue were semiquantitatively measured with immunohisto-chemistry and reverse transcriptase polymerase chain reaction (RT-PCR), respectively.The serum creatinine, urea nitrogen level, renal tubular injury score and expression ofKIM-1, TNF-α, NF-κB in renal tissue were compared between the two groups of ratsin the corresponding time point. The correlation among expression of TNF-α, NF-κBand tubular injury score, KIM-1expression in renal tissue of CIN group rats wereanalysised.Results:1. Scr, BUN level：The Scr and BUN level of Control group is littlechange(p>0.05). But the levels of Scr and BUN increased significantly in the CINgroup after12h from intravenous injection, its peak is at72h, so the CIN model hassucceed. The level of Scr and BUN in CIN groups displayed a significant increase at12h,24h,48h,72h,5d and10d compared with Scr and BUN level of control group(p<0.05).2.Histopathologic degrees of renal tubular cell injury: The histologicalexamination with HE-stain revealed renal tubular injury start at6h after injectingiodinated contrast media. Renal sections showed different extents of acute tubularinjury with tubular brush border loss, cell, degeneration and necrosis and regeneration,focal structure damage, which were more severe in medulla than those in corticaltissue at24h,48h. In addition, there are some inflammatory cell infiltration andfibrosis in the renal interstitial. Renal tubular began to repair from72h, and returnedto normal at15d. The level of renal tubular injury score in CIN groups is significanthigh at all time points compared with that of control group (P<0.05).3. Result ofimmunohistochemistry and RT-PCR: The protein and mRNA expressions of KIM-1,TNF-α and NF-κB start up-regulated significantly at6h, and the peak of KIM-1expression was at24h, while the peak expressions of TNF-α and NF-κB were at48h.The expressions of KIM-1, TNF-α and NF-κB were significantly increased in CINgroup compared with that in control group at other time points except at15d(P<0.05).4. Correlation analysis: The protein and mRNA expression of TNF-α (r=0.758,0.707,P<0.05) and NF-κB (r=0.843,0.743,P<0.05) showed closely correlation with renaltubular injury score. The protein expression of TNF-α and NF-κB were positivelycorrelated with protein expression of KIM-1(r=0.807,0.863,P<0.05). The expressionsof TNF-αmRNA and NF-κB mRNA were also positively correlated with expressionof KIM-1mRNA (r=0.855,0.839,p<0.05).Conclusion：1.Upregulated the expressions of TNF-α, TNF-αmRNA, NF-κBand NF-κB mRNA in renal tissue of CIN group rats.2.The expression of TNF-α,TNF-αmRNA, NF-κB and NF-κB mRNA are closely related with renal tubular injury.3.There are inflammatory response in the pathogenesis of CIN. |
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