| Objective: Renal ischemia reperfusion injury (IRI) is animportant histopathology mechanism of acute kidney injury(AKI). AKI causedby IRI is an important clinical problem, Despite the treatments of AKI isimprovement, it is also associated with significant morbidity and mortality. Themechanism of renal IRI is complex, it is still not clear, which involving freeradical, endothelial dysfunction, inflammation, injury and cell necrosis andapoptosis, etc. Oxidative stress has been shown to produce reactive oxygenspecies(ROS) that play an important role in the renal IRI. Under the conditionof hypoxia, a variety of cells may produce secreted matrix proteinsthrombospondin-1(TSP-1).TSP-1seldom express in normal kidney tissue, butrecent studies show that TSP-1is associated with the occurrence anddevelopment of AKI, closely related with the progress of chronic kidney disease.Therefore, The position of TSP-1in acute or chronic kidney disease (CKD) hasattracted much attention. CD47is Also known as integrin related proteins (IAP),is one cognate receptor of TSP-1, which is widely expressed in the kidney, butit’s mechanism of promote renal injury in essence and stromal cells also unclear.Therefore, This study was to establish a rat model of renal IRI, observed TSP-1and its ligand CD47distribution in kidneys of IRI and the expression changes, observed the change of blood ROS and the changes in oxidative stressindicators of kidney tissues. Study the expression and distribution of TSP-1andCD47in the renal IRI, and research the relationship TSP-1and CD47withoxidative stress, To discuss its role in the pathogenesis of renal IRI.Methods: A total of42male Sprague-Dawley rats were randomly dividedinto:normal group(n=5), sham group(n=5) and IRI group(n=32). IRI group weredivided into four time points：1hour、6hour、12hour、24hour，each time pointcontain8animals. Surgical Procedure: After the rats were anesthetized, midlinelaparotomy, both renal were exposed, bilateral renal blood flow were interruptedfor45min by applying rubber strips that wrapped in the vessels outside andligation. Rubber strips were removed and blood flow restored at the end of45min of ischemia. Observe the color change of the kidneys in the wholeoperation process. Close the belly and recovery. Observe the urine volume ofeach group. Detect renal function to know the renal damage, throughhematoxylin-eosin staining(HE) and periodic acid-schiff stain (PAS)understanding the renal pathological damage, mesangial matrix of all groupswere observed by the transmission electron microscopy to learn whether theywere thickened and whether the podocytes had any damage, to understand thesystemic oxidatie stress when renal IRI through detect the ROS of erythrocyteby flow cytometry and using enzyme-linked immunosorbent methoddetermination the concentration of hydroxyl free radicals and malondialdehyde in kidney tissues. the expression of TSP-1and CD47was measured byimmunohistochemical. To understanding whether TSP-1and CD47is commonexpression in the renal IRI by immunofluorescence double dye.Results: Compared with the normal group and the sham group, urineoutput were remarkably decreased in IRI groups, Levels of serum creatinine(Scr)and blood urea nitrogen(BUN). Along with the time extension after ischemiareperfusion, Tubular can appearing vary degrees of luminal expansion anddegeneration and necrosis and interstitial inflammatory cell infiltration andcongestion and edema and so on. The difference of pathology score isstatistically significant(P＜0.05). Mesangial matrix of IRI groups were markeddysplasia and the foot disappear of podocytes observed through the transmissionelectron microscopy, And there was no statistically significant differencebetween the groups of IRI. With the extension of the time after reperfusioninjury, the positive rate of ROS fluorescence intensity in erythrocyte isgradually increased and the concentration of hydroxyl free radicals andmalondialdehyde in the kidney tissues is increased. At the early of theischemia-reperfusion injury, the expression of TSP-1and CD47in kidneytissues was gradually increased, At IRI24h it’s expression is still high inresidual renal. Immunofluorescence double dye found they are coexpression inrenal IRI renal tubules. Correlation analysis found that the positive rate oferythrocyte ROS fluorescence intensity was positively correlated with the concentration of hydroxyl free radicals and malondialdehyde, serum creatinine,blood urea nitrogen and renal tubular damage score, the expression of TSP-1and CD47, but positively correlation with podocyte count.Conclusion: Results show that stable model of renal IRI can be gained inrat by a simple surgical to incarcerate bilateral renal arteries. Oxidative stressreaction of systemic caused by renal IRI, it result in the renal tissue structuredamage, the podocyte damage and renal dysfunction. TSP-1and CD47expression significantly increased, it is closely related to the oxidative stressreaction. TSP-1and CD47is the early warning indicator of renal tubular injury,also continue express with the whole process of renal IRI, Joint with ROSparticipation the early damage of IRI and the progress of kidney disease. |
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