Screening Differentially Expressed Serum Proteins In Osteoarthritis Of Experimental Research By ITRAQ Labeling Coupled With 2DLC-MS/MS

Osteoarthritis is one of the most common joint disease, the main clinical manifestations are the slow development of joint pain, stiffness, swelling, joint dysfunction, and even disability of knee.With the advent of an aging society, increasingly rise in the incidence of the disease,osteoarthritis had a great influence on human health and the quality of survival, the study of its has become an important topic in the field of medicine. It is recognized at home and abroad that osteoarthritis is a kind of long-term chronic and indistinguishable disease.Diagnosis is usually based on clinical symptoms and imaging changes.The diagnosis is generally based on clinical symptoms and radiographic changes. However X-ray has a poor sensitivity and a relatively large precision error that does not allow an early detection of OA or the monitoring of joint damage progression. Therefore, it is a hot direction of the research to find biomarkers of osteoarthritis as OA early diagnostic.Prteomics is used to study the expression and the changes of function of proteins which were corrected with biological processes by the analysis of whole protein. Looking for specific markers and the study of the pathogenesis of diseases, it’s an effective and high-throughput method. Proteomics technology can get biomarkers while traditional ways can’t. At the same time, most of the tumor markers belong to the glycoprotein.In this study, serum of the OA of K-L 0、Ⅱ、Ⅳ groups were compared. We first screened out differential proteins with potential diagnostic value by proteomic technology. And then validated part of them and make further analysis. At the same time, lectin affinity microarray is used to identify specific serum glycoproteome profiles during the four groups.AIMS:To apply the isobaric tags for relative and absolute quantitation (iTRAQ) to identify proteins differentially in serums of each stages of osteoarthritis K/L classification, and to find out each stages of osteoarthritis of potential molecular markers.METHODS:Seventy-six female patients with knee osteoarthritis admitted in the First Affiliated Hospital of Guangxi Medical University from February 2012 to December 2013 were enrolled, and according to Kellgren-Lawrence (K-L) grading, the groups were subdivided into K-L 0, Ⅱ and Ⅳ group. Each group randomly selected 10 men and 10 women. Proteins differentially regulated in serums identified by the stable isotope 116,117,118 of the iTRAQ labeled, LC-MS/MS analysis, after the serums were subjected to high abundance proteins depletion. Finally, we analyzed the proteins identified by using bioinformatics software.RESULTS:169 proteins were identified through iTRAQ peptides experiments of different sample tages, Q-star mass spectrum identification and MASCOT library search.153 proteins were identified compare K-L 0 to K-L Ⅳ,153 proteins were identified compare K-L 0 to K-L Ⅱ,145 proteins were identified compare K-L Ⅱ to K-L Ⅳ.Western blot analysis was applied to detect part of proteins(ADIPOQ、CRP) and the results indicated the credibility of iTRAQ results.CONCLUSIONS:1. ITRAQ technology may help to identify novel serum markers for early diagnosis of OA. ITRAQ technology for proteomics serum biomarkers of osteoarthritis study has good application prospect.2.ADIPOQ was proved as a potential biomarker for the detection of early OA. Lipid metabolism disorders may be the root cause of osteoarthritis pathogenesis.