Nonlinear spectral imaging microscopy of rabbit aortic wall

Employing nonlinear spectral imaging technique based on two-photon-excited fluorescence and second- harmonic generation （SHG） of biological tissue, we combine the image-guided spectral analysis method and multi-channel subsequent detection imaging to map and visualize the intrinsic species in a native rabbit aortic wall. A series of recorded nonlinear spectral images excited by a broad range of laser wavelengths （730- 910 nm） are used to identify five components in the native rabbit aortic wall, including nicotinamide adenine dinucleotide （NADH）, elastic fiber, flavin, porphyrin derivatives, and collagen. Integrating multichannel subsequent detection imaging technique, the high-resolution, high contrast images of collagen and elastic fiber in the aortic wall are obtained. Our results demonstrate that this method can yield complementary biochemical and morphological information about aortic tissues, which have the potential to determine the tissue pathology associated with mechanical properties of aortic wall and to evaluate the phaxmacodynamical studies of vessels.