Ischemic postconditioning (IPo) attenuates ischemia-reperfusion injuries (IRI) in various organs, of both animals and humans. This study tested the hypothesis that IPo attenuates renal IRI through the upregulation of heat shock protein (HSP)70, HSP27 and heme oxygenase-1 (HO-1, also known as HSP 32) expression. Adult Sprague Dawley rats were subjected to bilateral renal ischemia for 45 min followed by reperfusion for up to 48 h. One group of rats received IPo prior to restoring full perfusion. Another group was administered 100 mg/kg HSP inhibitor quercetin, injected intraperitoneally 1 h prior to ischemia. Control rats received sham operations. Renal IR resulted in severe morphological and pathological changes, with increased serum creatinine and blood urea nitrogen concentrations. IR resulted in increased inflammation by inducing plasma tumor necrosis factor-α and renal nuclear factor kappa-light-chain-enhancer of activated B cells expression. IR also increased lipid peroxidation, as indicated by elevated malondialdehyde content, reduced superoxide dismutase activity and increased renal apoptosis. Renal HSP70, HSP27 and HO-1 mRNA and protein levels were increased by IR and further elevated by IPo. IPo attenuated these changes observed in pathology, lipid peroxidation, apoptosis and inflammation. Quercetin treatment abolished all the protective effects of IPo. In conclusion, this study showed that IPo can attenuate lipid peroxidation, apoptosis and inflammation as well as renal IRI by upregulating the expression of HSP70, HSP27 and HO-1.

PurposeOxidative stress was significantly associated with the development of malignancies. The purpose of this study was to evaluate the significance of serum total oxidant/antioxidant status in operable advanced gastric cancer patients.Materials and methodsA total of 284 patients who underwent curative resection for primary stage III gastric cancer were enrolled. Total oxidant status, total antioxidant status, and oxidative stress index (OSI) were evaluated within 24 hours before surgery, and compared with 120 healthy donors. The correlation between the OSI and survival outcome was analyzed by the Kaplan–Meier method with log-rank test and Cox’s regression methods, respectively.ResultsMean OSI of gastric cancer patients was higher than healthy controls (1.41±0.96 vs 0.78±0.42, P<0.001). All patients were stratified into two groups using the optimal cutoff value (1.42) of OSI using a sensitivity of 94.1% and a specificity of 64.0% as optimal conditions from receiver operating curve analysis. Patients with an OSI ≥1.42 had poorer mean overall survival (45.6 vs 29.8 months, P=0.022) and mean recurrence-free survival (43.3 vs 28.1 months, P=0.011) than patients with an OSI <1.42 in univariate analysis, and OSI was also confirmed as an independent predictor for survival for gastric cancer in multivariate analysis (hazard ratio, 0.541; 95% CI: 0.127–1.102; P=0.01).ConclusionPreoperative OSI can be considered as an independent prognostic factor for operable and advanced gastric cancer.