Research On Osteoarthritis By Fourier Transform Infrared Spectroscopy

Osteoarthritis?OA?is the most common chronic joint disease in the middle-aged and elderly population with high disability rates.Previous studies have suggested that OA is caused by articular cartilage damage,but more and more studies have indicated that OA is a disease caused by all tissue lesions in the joint.Articular cartilage and subchondral bone are regarded as a composite functional unit,and their structural and functional changes play an important role in the pathological process of OA.In the early stage of OA,it only shows that changes in component content or structure.However,there are no obvious clinical symptoms in this stage,and OA have developed to an irreversible degree in the middle and late stages,so it is necessary to find a new method for early diagnosis of OA.Infrared spectroscopy with spectral analysis can qualitatively and quantitatively obtain information on the molecular structure and component content of the sample.It combined with chemometric algorithms can be applied to data regression and classification.Based on this,Fourier transform infrared?FTIR?spectroscopic imaging technique was firstly combined with support vector machine?SVM?algorithm to realize classification and quantitative analysis of articular cartilage samples,and then FTIR spectroscopy with spectral analysis method was used to achieve the composition distributions and changes of articular cartilage and subchondral bone tissue.?1?The support vector classification?SVC?model was constructed to realize the recognition of healthy and 2-year OA samples,with the accuracy of 97.69%.?2?A robust support vector regression?SVR?model was established to obtain the spatial distribution of the main component content of2-year OA samples,which was consistent with the result of partial least squares regression.It was found that the loss of proteoglycans in OA,mainly in the superficial and transitional zones.?3?The content of type II collagen in different areas of articular cartilage in healthy,3-month OA and 7-month OA was achieved by using the characteristic peak integrated area ratio of 1338cm^-1 and Amide II.The results suggested that the content of type II collagen in OA samples decreased to varying degrees,and was more obvious in the deep zone.?4?Quantitative evaluation of mineral content,carbonate content,crystallinity,collagen maturity and acid phosphate content of subchondral bone at different depths in healthy,3-month OA and 7-month OA samples was firstly made by the infrared spectral analysis.The more obvious results were that mineral content increased with depth in healthy samples,while carbonate content showed opposite trend.The mineral content reduced obviously with OA duration,which was different with carbonate decreasing only at early stage of OA.The results indicated that the combination of FTIR spectroscopic imaging and SVM might be a promising approach for the diagnosis of the early OA,and the research on the collagen type of articular cartilage and the parameters of subchondral bone could provide new ideas for clinical diagnosis and targeted therapy of OA,which helped to better understand the pathogenesis and related pathological changes of OA.