The effects of hydrogen sulfide on microvascular circulation in the axial pattern flap ear model in hairless mice

Abstract

Background/purposeImproval of flap viability is one of the main purposes in reconstructive surgery. The endogenous volatile mediator hydrogen sulfide (H2S) exerts plenty beneficial effects on blood rheology and protects from ischemia reperfusion injury. MethodsTherefore this study analyzed whether H2S affects tissue necrosis and skin microcirculation during impaired perfusion in the axial pattern ear flap model in hairless mice. Necrosis and microcirculatory parameters were assessed by means of stereo- and intravital fluorescence microscopy before and immediately after flap creation as well as on days 2 and 4 after surgery. Treatment with H2S donor GYY4137 or its vehicle was performed either one-time after flap preparation or two-times with an additional injection on day 2. After 4 days ear tissues were taken and further analyzed histologically to study tissue edema. ResultsCompared to vehicle treatment, both one- and two-time treatment with GYY4137 significantly reduced tissue necrosis and improved microcirculation in the ear flap, apparently through capillary dilatation and increased functional capillary density. Histological analysis revealed a significantly reduced tissue edema formation in GYY4137-treated animals. While microcirculatory parameters in parts significantly improved by two-time GYY4137 treatment, ear thickness and edema formation were independent from treatment regime. ConclusionsIn summary H2S treatment is a promising attempt to improve microcirculation in critically perfused skin flaps and consequently to preserve flap viability.