Multiphotonic and Harmonic generation microscopy: an attractive labelfree imaging and non-destructive observation of collagenic and adiposetissues in pathological muscle context

Second harmonic (SHG) and third harmonic generation (THG) provide powerful tools for collagenic and adipose tissueimaging respectively in unstained section. These properties due to the multiphotonic excitation represent very promising approach to explore the state of various degenerative diseases associated with abnormal fibrotic and fat tissue. In this report, we use SHG/THG to explore the fibrotic and fat tissue in muscular dystrophy context using rat and dog model. By comparison with classical used immunolabeling dedicated to collagen, we confirmed that SHG microscopy has strong potentiality to follow the fibrosis content in the disease. We also demonstrated that THG can be used to follow the distribution of lipid bodies in cells and dystrophic tissue. Thanks to these properties, the combination of fluorescence and harmonic signals represent a promising way to monitor the course of the neuro muscular diseases as well as the efficacy of therapeutic strategies