Low-energy extracorporeal shock wave ameliorates ischemic acute kidney injury in rats

Background Low-energy extracorporeal shock wave (SW) improves ventricular function in ischemic cardiomyopathy through the upregulation of vascular endothelial growth factor (VEGF). VEGF is known to play important roles in acute kidney injury (AKI), and the present study investigates the efficacy of SW for AKI by renal ischemia-reperfusion (I/R) injury. Methods Male 8-week-old Sprague-Dawley rats were divided into the following groups: SW-treated I/R group (I/R-SW), untreated I/R group (I/R), and Sham group. To induce I/R, the left renal pedicles were clamped for 45 min. The I/R-SW group was treated with SW to both kidneys on the immediate postoperative period (day 0), days 1, 2, 7, 8, 9, 14, 15, and 16. Rats were killed on day 2 and day 20 to determine histology, renal function, and Vegf family mRNA expression. Results Plasma creatinine on day 2 was significantly lower in the I/R-SW group than in the I/R group. Light microscopy revealed significantly lower tubular injury scores for the outer medulla in the I/R-SW group than in the I/R group. Podoplanin-positive lymphatic vessels were significantly increased in the left (affected side) outer medulla in the I/R-SW group on day 20. The expression levels of Vegf in the right (intact side) cortex were significantly higher in the I/R-SW group than in the I/R group on day 2. Conclusion Shock wave ameliorated renal tubular injury and renal function in AKI model, through the stimulation of Vegf family expression and lymphangiogenesis. SW may be effective as a non-invasive treatment for ischemic AKI.