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Renal ischemia-reperfusion injury (renal ischemia / reperfusion injury, RI / RI) is clinically common pathophysiological phenomena play an important role in the pathological process of ischemic acute renal injury, multiple factors involved in the complex pathological process. Major injury free radical damage, leukocyte - endothelial cell interactions, intracellular calcium overload the vasodilator of NO reduce endothelin vasoconstrictor substances produce too much. Trihydroxy-3-methyl-glutaryl coenzyme A (HMG-COA) reductase inhibitors, statins by specific inhibition of the enzyme HMG-CoA can not be converted to mevalonate (MVA) mevalonate thus blocking the synthesis of cholesterol, and reduce blood cholesterol levels, and this effect has been widely used for clinical treatment of hyperlipidemia. The role of statins pleiotropic In addition to the lipid-lowering effects, recent studies also found that the kidneys have a protective function. Simvastatin and lovastatin can be induced by cultured human endothelial cells eNOS gene transcription activation, promotion of nitric oxide (NO) synthesis the NO expansion glomerular afferent and ball artery, reduced renal vascular resistance, so that the kidneys plasma flow and glomerular filtration rate increases. Also reported that statins reduced nicotinamide adenine dinucleotide phosphate (Nicotinamide adenine dinucleotide phosphate, NADPH) oxidase subunit expression, increase the activity of antioxidant enzymes, the intracellular antioxidant role, thereby reducing the oxygen free base or clear the body to produce oxygen free radicals, enhance the body's antioxidant capacity. Statin chemical methods such as the effect of simvastatin on RI / RI's role, and to explore the possible mechanism of action. Whether the drugs have a protective effect on ischemia-reperfusion injury kidney is rarely reported. So explore the protective effect of statins on ischemia-reperfusion injury in rat kidney and its mechanism of action on the prevention and treatment of RI / RI of great significance. The purpose of this experiment is to be applied physiology, biochemistry, molecular biology and immunohistochemistry Objective: To investigate the role of simvastatin on the RI / RI's and explore its possible mechanism of action. Methods: clamping bilateral renal artery, the vein 45 minutes the Zhong Housong clip reperfusion in the method produced RI / RI model, the effect of simvastatin on rats RI / RI injury. Healthy adult male Sprague-Dawley (SD) rats 60, weighing 150 to 180g, reared in the 18-22 ℃ laboratory of quiet two days later the animals were randomly divided into five groups, namely: (1) sham-operated group (Sham) (2 ) ischemia-reperfusion group (I / R) (3) low-dose simvastatin group 5mg/kg/d ischemia-reperfusion (Sim-L) (4) ischemia-reperfusion 20mg/kg simvastatin dose group / d (Sim-M) (5) ischemia-reperfusion simvastatin high dose group 40mg/kg/d (Sim-H) the animals grouped, SIM-L group were given daily simvastatin 5mg/kg orally, SIM-M group daily 20mg/kg orally SIM-H group daily 40 mg / kg orally for 2 weeks. Sham group and ischemia group daily to normal saline orally. 2 weeks after replication in animal models. Animals the abdominal cavity of 1% sodium pentobarbital anesthesia, laparotomy, exposure bilateral renal artery, vein. In addition to the sham-operated group only open occlusion of the renal artery and vein, the rest of the group dynamic clamping bilateral renal vein 45 minutes, then go to the folder reperfusion. The after reperfusion sutured the peritoneum, abdominal muscles and skin. Respectively, at 6 hours after reperfusion and 24-hour blood in batches and both kidneys serum creatinine (Scr), blood urea nitrogen (BUN), kidney tissue malondialdehyde (MDA), nitric oxide (NO)-induced type nitric oxide synthase (iNOS) content and superoxide dismutase (SOD) activity. Immunohistochemistry was used to observe renal tissue endothelial nitric oxide synthase (eNOS) expression of p47phox. Detected by Western blot renal tissue eNOS and p47phox protein expression levels. Results: 1. Renal ischemia-reperfusion injury, light microscopy findings: sham group no obvious abnormalities in renal tissue; I / R group renal tissue injury with ischemia reperfusion time gradually increased, the performance of renal tubular epithelial cells cloudy swelling, necrosis, lumen expansion, the tube visible casts and exfoliated cells, interstitial edema, nuclear chromatin edge set as well as the obvious cytoplasmic vacuolar degeneration. Sim-M and Sim-H group at each time point of renal tissue damage than I / R group significantly reduced, similar to the SIM-L group at each time point of renal tissue injury and I / R group. 2 rat kidney ischemia-reperfusion injury, renal I / R group decreased BUN and Scr were significantly higher than the Sham group (P lt; 0.01), and tended to be worse with prolonged ischemic time; and I / R group, Sim-L, SIM-M and SIM-H group at each time point BUN, Scr were significantly lower (P lt; 0.05 to 0.01). 3 renal ischemia-reperfusion injury after I / R group at each time point SOD activity was significantly lower than the Sham group (P lt; 0.01), MDA content was significantly higher (P lt; 0.01); with I / R group SIM-M group and Sim-H group at each time point SOD activity was significantly increased (P lt; 0.01), MDA content were significantly decreased (P lt; 0.01), the indicators of the SIM-L group and I / The R group did not change significantly. 4 renal ischemia-reperfusion injury, NO and iNOS content of the I / R group at each time point were significantly higher than the Sham group (P lt; 0.01); compared with the I / R group, SIM-M group and Sim -H group at each time point NO content increased significantly (P lt; 0.01), SIM-M group and Sim-H group the iNOS content decreased (P lt; 0.01); eNOS expression in renal cortex of the sham group, I / R renal increase in cortical eNOS expression compared with Sham group, compared with the I / R group, SIM-M group and Sim-H group at each time point a significant increase in the expression of eNOS; Western blot method renal tissue was detected eNOS protein content, the I / R group renal cortex eNOS protein content than the Sham group increased, SIM-M group and Sim-H group at each time point eNOS protein levels were significantly increased compared with the I / R group, SIM-L group and I / R group did not change significantly compared to . 5 rat renal ischemia-reperfusion injury, renal cortex p47phox expression compared with Sham group significantly increased, renal tissue was detected by Western blot method p47phox protein content, I / R renal cortex p47phox protein content compared to the Sham group increased significantly; and I / R group, SIM-M group and SIM-H group at each time point p47phox expression and protein levels were significantly reduced. SIM-L group no significant change compared with the I / R group. Conclusion: RI / RI, renal function was significantly impaired. Renal tubular epithelial cell swelling, necrosis, interstitial edema. RI / RI rats BUN, Scr, MDA and iNOS content than those in the sham group significantly increased SOD activity and expression of eNOS was significantly reduced compared with the sham group, the renal cortex the p47phox immune reaction positive granules and protein expression were significantly increased. Indicating that p47phox involved in renal ischemia / reperfusion injury, and played an important role. Simvastatin can significantly reduce the RI / RI rats BUN, Scr and MDA content in to improve renal tissue SOD activity. Reduce renal tissue iNOS content, to increase the eNOS immunoreactivity particles and protein expression, increased NO content. Showed that simvastatin reduce the RI / RI rat kidney tissue damage and improve kidney function. Simvastatin significantly reduced ischemia-reperfusion injury in rat renal cortex p47phox immunoreactive particles and protein expression, reduce renal ischemia-reperfusion injury. Showed that simvastatin reduce the RI / RI renal tissue injury mechanism may be related to the decrease p47phox expression level of interference generated path NAD (P) H oxidase, anti-free radical damage.
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