Protective Effect And Mechanism Of Cnp On Renal Ischemia Reperfusion Injury In Rats

Purpose:Study on effect of C type natriuretic peptide on renal ischemia reperfusion injury in rats.Methods:Wistar rats, male or female, weight230+20g, right nephrectomy, left renal artery clamping24hour reperfusion model closed45minutes after renal ischemia. Divided into renal ischemia reperfusion group (group IR), sham operation group (Sham group), CNP group (group CNP),3groups,10rats in each group. Each treatment separately as follows:Sham group without clamping the right renal artery and vein, suture after24h based experiment, IR group of clamping the right renal arteriovenous45min immediately after reperfusion was given after suture24h experiment, CNP group of clamping the right renal artery and vein and femoral venous continuous infusion of CNP (1μg/kg/min), After24hours of reperfusion following experimental materials.Results:1.The changes in renal tissues pathology:Sham operation group kidney structure clear, no atrophy of glomeruli, renal tubular epithelial cell integrity; Macroscopic observation of ischemic reperfusion group (I/R24h group) showed increased kidney, renal medullary part is dark red. Microscopic observation of severe vascular congestion and hemorrhage of renal tubules and renal parenchyma in visible, erythrocyte aggregation, necrotizing precipitation, glomerular degeneration, interstitial edema, swelling and necrosis in the lumen formation degeneration, eosinophilic casts; CNP gives the medicine group (group CNP24h) renal parenchyma were nearly normal rules, tubular are basically normal, inflammatory cell infiltration was not obvious, mainly simple renal interstitial edema and hyperemia.2. Sham operation group (Group sham) and ultrastructural basically normal, ischemia reperfusion injury group (I/R24h group) were observed in renal tubular epithelial cell shedding, necrosis, edema, mitochondria mitochondrial crista disappeared, and even the emergence of basement membrane rupture; CNP group (group CNP24h) renal parenchyma were nearly normal rules, renal tubular arrangement the basic normal, inflammatory cell infiltration was not obvious, mainly simple renal interstitial edema and hyperemia.3. Renal tissue TUNEL staining:sham operation group only a few scattered apoptotic cells in I/R group; the number of TUNEL positive cells were mainly distributed in the outer medulla, distal convoluted tubule, a small amount of the distribution in the cortical tubules, some fall off into the renal tubules; TUNEL positive cells in CNP group only a few.4.Determination of the content of serum cGMP:The content of cGMP in sham operation group than those in I/R group and CNP treatment group, CNP treatment group compared with I/R group, the cGMP content increased.5. Expression of Bax, Bcl-2protein expression in renal tissue:sham operation group and CNP instant delivery group than in the I/R group, the expression of renal tissue antibody Bax significantly increased (n=10, P<0.05), and sham group, I/R group, CNP group, the three groups had no significant difference in Bcl-2expression between antibody.Conclusions:1.CNP on renal ischemia reperfusion injury was improved effect of organizational structure and function.2.CNP has significant anti injury, anti-apoptotic and anti-oxidative effects on renal tissue after ischemia.3.CNP anti-apoptotic effect, its function is accomplished by NP-cGMP signal pathway.