Discovery of Serum Proteomic Biomarkers for Prediction of Response to Moxibustion Treatment in Rats with Collagen-Induced Arthritis: An Exploratory Analysis

Abstract

Objective To examine the possible impact of moxibustion on the serum proteome of the collagen-induced arthritis (CIA) rat model. Materials and Methods Thirty-six male Sprague-Dawley rats were included in this experiment. The CIA animal model was prepared by injection of type II bovine collagen in Freund's adjuvant on the first and seventh day. The 36 rats were randomly divided into two groups: the untreated CIA group (control), and the CIA plus treatment with moxibustion (CIA+moxi) group. Moxibustion was administered daily at ST36 and BL23 for 7, 14 or 21 days (n=12 rats each). Arthritis score was used to assess the severity of arthritis. At the end of each 7 day treatment, blood samples from the control group and the CIA+moxi group were collected. After removal of high abundance proteins from serum samples, two-dimensional gel combined with matrix-assisted laser desorption ionisation time-of-flight MS/MS (MALDI-TOF-MS/MS) techniques were performed to examine serum protein expression patterns of the CIA rat model with and without moxibustion treatment. In addition, the relevant proteins were further analysed with the use of bioinformatics analysis. Results Moxibustion significantly decreased arthritis severity in the rats in the CIA+moxi group, when compared with the rats in the CIA group 35 days after the first immunisation (p=0.001). Seventeen protein spots which changed >1.33 or <0.77 at p<0.05 using Bonferonni correction for multiple testing were found to be common to all three comparisons, and these proteins were used for classification of functions using the Gene Ontology method. Consequently, with the use of the Ingenuity Pathway Analysis, the top canonical pathways and a predicted proteomic network related to the moxibustion effect of CIA were established. Conclusions Using the proteomics technique, we have identified novel candidate proteins that may be involved in the mechanisms of action underlying the beneficial effects of moxibustion in rats with CIA. Our findings suggest that immune responses and metabolic processes may be involved in mediating the effects of moxibustion. Moreover, periodxiredoxin I (PRDX1) and inositol 1,4,5-triphosphate receptor (IP3R) may be potential targets.