Laser speckle contrast imaging as a better tool to access the cutaneous microcirculation: Reproducibility and comparison to laser Doppler imaging in animal models

Abstract

Current assessment of skin microcirculation function in animal models use laser Doppler flometry (LDF) or laser Doppler imaging (LDI). Both methods are limited by either low spatial resolution (LDF) or low temporal resolution (LDI). Laser speckle contrast imaging (LSCI) is a novel imaging technique of the cutaneous microcirculation with high spatial and temporal resolution. In this study, we report the use of LSCI in C57Bl/6 J mice in baseline flux, current induced vasodilation (CIV) and in wound healing monitoring (WHM) of excisionnal wound over 8 days. We describe the use of two high-resolution LSCI devices and compare them to LDI. To compare inter-day or/and inter-subject reproducibility of LSCI and LDI in CIV and WHM. Reproducibility will be expressed as coefficient of variation and intraclass coefficient correlation. Animal experiments were performed on 10-week-old C57Bl/6 J mice. CIV was produced by the administration of 100 μA of cathodal current over 4 min using a 1 cm 2 woven silver electrode with carboxymethylcellulose gel (Suprasorb G) as the electric diffusion layer. WHM was performed daily over 8 days after two 6 mm 2 wound were created on the back skin of the mice. Skin perfusion was assessed on the wound area and the periulcer skin. Both tested LSCI devices presented high resolution to 20 μm/pixel which allowed for the accurate mapping of the skin microcirculation in mice. Reproducibility data will be presented at the congress. LSCI is useful in assessing the cutaneous microcirculation compared to LDI. Additional testing is required such as skin microvascular reactivity to iontophoresis of acetylcholine and sodium nitroprusside and pressure ulcers for wound healing monitoring.