Study On The Pathological Factors During Spinal Cord Injury And Its Low-level-laser Treatment By Using Confocal Raman Spectral Imaging Method

Confocal Raman microscopy imaging(CRMI)is a kind of detection and analysis method combining microimaging and Raman spectroscopy,which has the advantages of spatial resolution,measuring sensitivity and nondestructive examination.According to the spectral and image analysis,the detailed biochemical components and spatial distribution can be obtained easily,making CRMI have the significant application in biology,archaeology and other aspects.In this work,the biochemical structure of healthy spinal cord,pathological changes of spinal cord injury(SCI)as well as the mechanism of low-level laser therapy(LLLT)were all analyzed by CRMI respectively.In this paper,the physiological characteristics of spinal cord and the causes of SCI are described at first.In addition,the principle of Raman spectrum and CRMI is also introduced as well as the data processing method used later.In the experiment,in order to assess the ability of CRMI application in the aspect of spinal cord pathology,normal human spinal cord sections were firstly used for spectral acquisition and scanning.The spectra of white and gray matter neighboring the ventral horn of gray matter and two-dimensional distribution images of different components were obtained,revealing the differences of biochemical composition between white and gray matter,which also consistent with the existing spinal cord histological findings.After validating the feasibility and reliability of CRMI,in order to research the rat spinal cord injury model in the future,the biochemical characteristics of normal rat spinal cord must be measured and analyzed distinctly.During the measurement,the single spectral processing and Raman image reconstruction were combined with multivariate analysis method(such as K-mean cluster analysis)to classify and visualize the tissue structure.The physiological characteristics of spinal cord were analyzed with the distribution pattern of biochemical components and the morphological basis,establishing the accurate relationship between the featured spectra and the molecular composition of normal rat spinal cord.In the study of SCI and LLLT mechanisms,areas neighboring the injury site,glair scar,cavities and unharmed white matter can be identified by CRMI with some pathological phenomena including demyelination and chondroitin sulfate proteoglycans(CSPGs) aggregation.Besides,the multivariate and statistical analysis methods were used to describe the detailed changes of CSPGs,lipids and phosphatidic acid during the SCI and LLLT process.It was confirmed that not only can the light-tissue interaction inhibit the expression of CSPGs,but also promote the sprouting and regeneration of axons,resulting the decrease of the area of cavities and glair scar.Achieving the analysis of pathological changes of spinal cord injury site by CRMI,the work further illustrated the pathological mechanism of LLLT for SCI,providing a solid theoretical support and technical guidelines for the clinical research in the future.