Applications Of Label-free Multiphoton Microscopy In The Field Of Brain Diseases

Brain disease is a major health challenge for China and the world.The incidence of brain diseases has increased significantly in the past 20 years,which has brought a heavy burden to our society.Therefore,as the most complex system in the human body,novel techniques that can effectively diagnose brain diseases,which have become a hot research topic at home and abroad.Although the development of advanced imaging technology has significantly improved the diagnosis of brain diseases,the characteristics of early lesions and neurodegenerative diseases are still unclear.Moreover,the imaging resolution is generally only millimeter,which cannot be used as the final clinical diagnosis.Furthermore,identified diagnosis must need staining or specific immunohistochemical procedures.Thus,label-free medical imaging technology with histopathological high resolution and rapid pathological diagnosis,which will provide important support for intraoperative and postoperative clinical pathological diagnosis,as well as become an urgent need of clinical medicine.Multiphoton microscopy(MPM)is an advanced medical imaging technique based on the interaction between laser and biological tissue,which can generate strong two-photon excitation fluorescence and second-harmonic generation signals without any fluorescence molecular probe in biological tissues.Moreover,MPM has unique advantages such as low damage,high sensitivity,high spatial resolution,and subcellular-level imaging,it has been widely used in various fields of life science.Here,we developed and broadened the appilication of label-free MPM in brain diseases,foused on normal brain structure,brain tumors,ischemic stroke,focal cortical dysplasia(FCD),and Alzheimer's disease(AD).The main contents are as follows:(1)In normal brain structure research,we can not only analyze the MPM features of cerebral cortex,hippocampus,and different cell types,but also determine the source of endogenous signals in brain tissue.The feasibility of MPM in the application of brain imaging was preliminarily verified.(2)In brain tumor research,tumor core and tumor peripheral areas can be identified by combining MPM with programmable image processing,which proposed a potential new method for rapid visualization of cerebellar tumor pathology.(3)In ischemic stroke research,MPM identified cortical and striatal neuronal morphological changes at different time points of cerebral ischemia,evulating the temporal and spatial progression of cerebral infarction pathology.(4)In epilepsy research,the combination of MPM and image processing can serve as a quantitative methodology for rapid identification of FCD specimen.(5)In AD research,we revealed extracellular A? plaques and intracellular A? accumulation,as well as to distinguish and visualize different degrees of A? deposition by combining with programmable image processing programs.Our results verify the feasibility of the appilication of label-free MPM in brain imaging,show a new method for studying brain diseases,and provide a strong basis for the rapid pathological diagnosis and clinical application of MPM in the future.