A new mouse model of hemorrhagic shock-induced acute kidney injury

Current animal models of hemorrhagic shock-induced acute kidney injury (HS-induced AKI) require extensive surgical procedures and constant monitoring of hemodynamic parameters. Application of these HS-induced AKI models in mice to produce consistent kidney injury is challenging. In the present study, we developed a simple and highly reproducible mouse model of HS-induced AKI by combining moderate bleeding and renal pedicle clamping, which was abbreviated as HS-AKI. HS was induced by retroorbital bleeding of 0.4 ml blood in C57BL/6 mice. Mice were left in HS stage for 30 min, followed by renal pedicle clamping for 18 min at 36.8-37.0°C. Mean arterial pressure (MAP) and heart rate were monitored with preimplanted radio transmitters throughout the experiment. The acute response in renal blood flow (RBF) triggered by HS was measured with transonic flow probe. Mice received sham operation; bleeding alone and renal pedicle clamping alone served as respective controls. MAP was reduced from 77 ± 4 to 35 ± 3 mmHg after bleeding. RBF was reduced by 65% in the HS period. Plasma creatinine and kidney injury molecule-1 levels were increased by more than 22-fold 24 h after reperfusion. GFR was declined by 78% of baseline 3 days after reperfusion. Histological examination revealed a moderate-to-severe acute tubular damage, mostly at the cortex-medulla junction area, followed by the medullar and cortex regions. HS alone did not induce significant kidney injury, but synergistically enhanced pedicle clamping-induced AKI. This is a well-controlled, simple, and reliable mouse model of HS-AKI.