Hyperspectral Imaging Quantification of Mouse Limb Microcirculation Using an Ischemia Reperfusion Model with Phosphodiesterase 5 Inhibitor Preconditioning

Background:Peripheral arterial disease has high incidence and complication rates. Vessel recanalization represents the main therapy. However, it induces reperfusion injury. Preconditioning with sildenafil has been advocated to protect against this injury. In this study, we show a real-time noninvasive quantitative assessment using hyperspectral imaging (HSI) of ischemia/reperfusion (IR) and analyzing the sildenafil effect. Materials and Methods:A one-sided hindlimb ischemia (120 minutes) followed by reperfusion (30 minutes) was created. Five mice received Sildenafil (1 mg/kg, i.p. twice before ischemia) and 5 mice served as control. The StO(2)at T0, 5, 30, 60, 120 minutes after ischemia (T5, 30, 60, 120) and 5, 15, and 30 minutes after reperfusion (T125, 135, 150) were measured through HSI. Results:The control group showed a significantly lower StO(2)at T120 (24.8% +/- 17%) as compared with T0 (53.3% +/- 7.04%) (P = .013) and T150 (76.8 +/- 3.77;P = .0008). T150 showed a statistically significantly higher StO(2)than T0 (P = .0134). In the sildenafil group, T120 StO(2)(28.6% +/- 20%) was lower than T0 (63.3% +/- 8.46%;P = .0312) and T150 (73.3% +/- 19.1%,P = .0075). The StO(2)values did not differ statistically between sildenafil and control groups. Conclusions:HSI is a feasible tool to quantify both ischemia and reperfusion phases during lower limb IR. Preconditioning with sildenafil did not modify IR-related StO(2)changes.