Abstract
We have developed a multimodal nonlinear optical microscopy system to observe stimulated Raman scattering (SRS), coherent anti-Stokes Raman scattering (CARS), second harmonic generation (SHG), and two photon excitation fluorescence (TPEF) images simultaneously. By using the developed system, we observed atheroscleortic plaques formed in the aorta samples of spontaneously hyperlipidemic mice with apolipoprotein E deficiency. The histological structure of lipid, collagen, and elastin were visualized with SRS/CARS, SHG, and TPEF, respectively. The usefulness of SRS comparing with CARS for imaging of lipid distribution was also demonstrated because CARS images have high background signals originated from non-resonant background and/or autofluorescence of elastin. Three-dimensional reconstruction images of SRS/CARS/SHG/TPEF enabled to visualize the non-invasive three-dimensional tissue structure and detection of factors determining the plaque vulnerability including abnormally produced collagen and fibrous cap. The usefulness of the multimodal nonlinear optical microscopy system for the histological assessment and quantitative evaluation of the atherosclerotic lesion was demonstrated.
