Study Effects Of Glucose On Blood Vessels Using Laser Speckle Imaging Technique

Recently, tissue optical clearing technique becomes one of the hot spots in the research field of biomedical optics, however, quantitative research towards the change of blood vessels and flow caused by optical clearing agents is very little. Laser speckle contrast imaging (LSCI) can measure the regional blood flow dynamics with high spatial and temporal resolution, but the results will be affected with the variation of the scattering properties of the background tissue in the process of optical clearing. Therefore, we first evaluate the correctness of the LSCI results measured in the optical clearing progress, then we provide further investigations to the influence of blood vessels on chick chorioallantoic membrane (CAM) caused by glucose solution, and analyze the different responses of blood vessels on CAM with different embryo ages. At last, we provide the safety evaluations of glucose solution as an optical clearing agent through the experiments on hamsters.The research content and main results includes(1) We use an experimental model to mimic the tissue optical clearing process, and investigate the measurement errors of LSCI caused by the variations of scattering coefficients of tissue. We find that the velocity measurements of LSCI decrease when scattering coefficient of tissue reduces.(2) We investigate the short-term and long-term effects of glucose solution with different concentrations on CAM blood vessels. We find that the effects on CAM blood vessels are directly relate to the osmolarity of glucose solution. The higher osmolarity, the bigger effects.(3) We investigate the differences of chick embryos'tolerances with different embryo ages. We find that the short-term and long-term effects of glucose solution on EA-11 CAM are weaker than on EA-8 CAM. The results show that the differences of chick embryos'tolerances can result in different safety conclusions of the glucose solution.(4) We investigate the effects of 40% glucose solution on dermis using hamster dorsal skin flap window. The results obtained by LSCI show that 40% glucose solution only cause limited effects on blood vessels beneath the skin, and the effects will be eliminated in 5 hours. So, we consider it will be safe to hamsters'skin after the injection of 40% glucose.