Effects of Depilation-Induced Skin Pigmentation and Diet-Induced Fluorescence on In Vivo Fluorescence Imaging

Near-infrared fluorescence imaging (NIRFI) and far-red fluorescence imaging (FRFI) were used to investigate effects of depilationinduced skin pigmentation and diet-induced background fluorescence on fluorescent signal amplitude and lymphatic contraction frequency in C57BL6 mice. Far-red fluorescent signal amplitude, but not frequency, was affected by diet-induced fluorescence, which was removed by feeding the mice an alfalfa-free diet, and skin pigmentation further impacted the amplitude measurement. NIRFI showed minimal background fluorescence; however, skin pigmentation reduced the amplitude of fluorescent signal changes. Therefore, these effects should be taken into account when imaging mice with different states of skin pigmentation and diet-induced background fluorescence in vivo.