The protective roles of zinc and estradiol in renal ischemia/reperfusion injury in ovariectomized rats

Background: One of the main events associated with ischemia/reperfusion injury (IRI) is excessive production of reactive oxygen species (ROS).Zinc (Zn) and estradiol are considered as antioxidants that scavenge free radicals.Objectives: The aim of this study was to compare the protective effect of Zn and estradiol against renal IRI in ovariectomized rats.Materials and Methods: Ovariectomized Wistar rats were randomly divided into five experimental groups including control (sham operated), IRI, estradiol treated +IRI, estradiol and Zn treated +IRI, Zn treated +IRI groups.The IRI was induced by clamping renal vessels for 45 minutes followed by 24 hours reperfusion.During the last 6 hours of reperfusion, urine output was collected and the measurements were performed.Results: IRI caused an increase in kidney tissue damage score (KTDS) significantly (P < 0.05).The serum levels of blood urea nitrogen (BUN) and the creatinine (Cr) also elevated by IRI, but theses parameters attenuated by Zn treatment significantly (P < 0.05).Cr-clearance and urine flow were increased by Zn, and the percent of sodium excretion was increased by estradiol significantly (P < 0.05).The kidney tissue level of malondialdehyde was decreased by co-treatment of Zn and estradiol statistically (P < 0.05).Conclusions: Zn protected the kidney against IRI with an evident improvements of serum BUN and Cr levels, Cr clearance and tissue damage.