| Objectives:The objective of this study was to explore the pathogenesis of contrast induced nephropathy (CIN) by observing the pathological changes of rat kidney and the changes of serum creatinine (Scr), interleukin-6(IL-6), high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-a (TNF-a), renal tissue malondialdehyde (MDA), superoxide dismutase (SOD), nitric oxide (NO), endothelin (ET-1), vascular endothelial growth factor (VEGF) and apoptosis index (Bcl-2, Bax) levels in the rat models of CIN.Methods:1. induction of CIN in rats:30male Wistar rats were randomly divided into two groups:experimental group and control group, with15rats in each group. All rats were feeding for7days. The first day of the experiment, rats in the both groups were treated with intraperitoneal injection of pentobarbital to anesthesia, then peeled femoral vein and drew blood2ml separately. The control group and experimental group were given saline10mg/kg intravenously and urografin10mg/kg intravenously, respectively. We drew2ml blood from inner canthus of the rats after48h and72h the angiography.72h after the angiography, the rats were killed, then removed the kidneys and separated the cortex and medulla. If there were an increase in Scr levels≥25%from base line, CIN model were successfully established.2. specimen processing:All blood samples were centrifuged to determine the levels of Scr, IL-6, hs-CRP, TNF-a. Left renal cortex stored at-80℃refrigerator to determine the expression levels of MDA, SOD, NO, ET-1, VEGF and Bcl-2, Bax in renal tissue. Most of the right kidney cortex paraffin was embedded for HE staining and immunohistochemical staining, and the rest was made of a small portion of1mm3immersed in glutaraldehyde phosphate buffer solution for electron microscopy specimen.Results:1. serological markers:there were no significant differences in the levels of Scr, IL-6, hs-CRP and TNF-α (P>0.05) before angiography of two groups.48h after angiography, levels of Scr, IL-6and hs-CRP were significantly higher in the experimental group than levels in the control group (P<0.05).72h after angiography, levels of Scr and hs-CRP were significantly higher in the experimental group than levels in the control group(P<0.05). 2. renal tissue markers:72h after angiography, the content of MDA, ET-land Bax in renal tissue of the experimental group were higher than in the control group, the difference was statistically significant (P<0.05); Bcl-2levels in the experimental group were lower than levels in the control group (P<0.05). The expression of VEGF in kidney tissue was higher in the experimental group than in the control group (80%VS26.67%, P<0.05).3. histological changes:light microscopy showed:there were vacuolation, cytoplasmic degeneration in tubular epithelial cell, even the structure of small tube disappeared and karyopyknosis, pyknosis in the experimental group; renal tubules and interstitium were infiltrated by inflammatory cell visibly; there was protein tube lumen in cavity of renal tubules, even luminal occlusion; renal artery expanded and congested; glomerular structure showed no abnormalities. The control group tubular and glomerular were normal mainly. Electron microscope showed:the basement membrane of renal tubular were thickened severely; endoplasmic reticulum and mitochondria in the endothelial cells were swelled, the arrangement of crista disordered, or even disappeared; a large number of microvilli sheded in luminal surface in the experimental group. In the control group, the renal tubules and the glomerular ultrastructure were normal.Conclusion:1. This research successfully established CIN models in rats by injecting urografin and the results are stable, high repeatability.2. CIN may be a result of the complex effects of the pathogenesis of oxidative stress, inflammation, kidney vasomotor instability, apoptosis, and direct renal toxicity related injury. |
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