A simple method of optical evaluation of the distribution of muscle extracellular matrix by immunofluorescence and image analysis using fluorescent semiconductor nanocrystals (quantum dot)

A simple method using optically stable quantum dots (Qdots) for immunohistochemical (IHC) analysis was tested to investigate their signal localization and stability in extracellular matrix (ECM) components of bovine longissimus thoracis muscles in fattened Japanese black steers. Detection of primary antibodies of each ECM component in IHC was based on fluorescence from streptavidin-linked inorganic crystals of cadmium selenide in Qdots with a fluorescence microscope (FM). We could observe each ECM component by IHC using Qdots in a FM for a long time. Each ECM component was detected clearly in the perimysium and endomysium in skeletal muscle. Using computer image analysis software, each ECM component was reconstructed in detail: structures were clear, with the distribution of each component of the ECM shown after 3D conversion based on the strength of fluorescenece. It is possible and useful to apply a simple method of IHC using Qdots under FM to the detailed investigation of ECM components in skeletal muscle.