Background and purpose: Extended warm ischemia time during partial nephrectomy leads to considerable renal injury. Using a rat model of renal ischemia, we examined the ability of a unique renoprotective cocktail to ameliorate warm ischemia-reperfusion injury and extend warm ischemia time.
Materials and methods: A warm renal ischemia model was developed using Sprague-Dawley rats, clamping the left renal artery for 40, 50, 60, and 70 minutes, followed by 48 hours of reperfusion. An improved renoprotective cocktail referred to as I-GPM (a mixture of specific renoprotective growth factors, porphyrins, and mitochondria-protecting amino acids) was administered -24 hours, 0 hours, and +24 hours after surgery. At 48 hours, both kidneys were harvested and examined with hematoxylin and eosin and periodic acid-Schiff stains for the analysis of renal tubular necrosis. Creatinine, protein, and gene expression levels were also analyzed to evaluate several ischemia-specific and antioxidant response markers.
Results: I-GPM treated kidneys showed significant reversal of morphologic changes and a significant reduction in specific ischemic markers lipocalin-2, galectin-3, GRP-78, and HMGB1 compared with ischemic controls. These experiments also showed an upregulation of the stress response protein, heat shock protein (HSP)-70, as well as the phosphorylated active form of the transcription factor, heat shock factor (HSF)-1. In addition, quantitative RT-PCR analyses revealed a robust upregulation of several antioxidant pathway response genes in I-GPM treated animals.
Conclusions: By histopathologic and several molecular measures, our unique renoprotective cocktail mitigated ischemia-reperfusion injury. Our cocktail minimized oxidative stress in an ischemic kidney rat model while at the same time protecting the global parenchymal function during extended periods of ischemia.