Protective Effect of Nicotinamide Adenine Dinucleotide Phosphate on Renal Ischemia-Reperfusion Injury

Renal ischemia-reperfusion injury (IRI) is a common consequence of acute kidney injury. Nicotinamide adenine dinucleotide phosphate (NADPH), which is derived from the pentose phosphate pathway, is essential for the proper functioning of essential redox and antioxidant defense systems. Previous studies have indicated that NADPH is responsible for protecting the brain from ischemic injury. The goal of this study was to analyze the protective function of NADPH in renal IRI.

The IRI animal model was generated through a midline laparotomy surgery that clamped both sides of the renal pedicles for 40 min to induce renal ischemia. The in vitro model was generated by removing oxygen and glucose from human kidney epithelial cells (HK-2 cells), followed by reoxygenation to imitate IRI. Renal function and histopathological changes were observed and evaluated. Additionally, malondialdehyde and glutathione levels were determined in renal tissue homogenate as indicators of oxidative stress. ROS production in cells was determined by DHE staining. Protein biomarker expression was evaluated by western blot, apoptosis was analyzed by TUNEL staining, and p65 nuclear translocation was visualized by immunofluorescence.

Our data indicated that NADPH safeguarded the kidneys from histological and functional damage, and significantly reduce cell injury along with preventing potential increases in blood urea nitrogen and creatinine levels. Furthermore, we observed that NADPH increased glutathione levels, while reducing levels of malondialdehyde and reactive oxygen species. Additionally, our results suggested that NADPH treatment may alleviate IRI-induced apoptosis and inflammation.

NADPH treatment may protect against renal IRI and should be further developed as a new treatment for acute kidney injury.