Metabolomics study of biochemical changes in the serum and articular synovium tissue of moxibustion in rats with collagen-induced arthritis

Objective:To demonstrate the rheumatoid arthritis(RA)mechanisms by determining the biochemi-cal changes.To investigate the therapeutic mechanism of moxibustion in RA-model rats using a gas chromatography-mass spectrometry(GC-MS)metabolomics approach. Methods:A total of 24 rats were divided into three groups as follows:normal control group,model group and moxibustion group.Rats in model group and moxibustion group were set up collagen-induced arthri-tis(CIA)model.Rats in moxibustion group were treated by moxibustion.After 3 weeks of intervention,right ankle joint,serum and articular synovium samples were collected.Right ankle joint samples were used for histopathological evaluation between 3 groups to get the pathological changes of tissues and cells.Serum and articular synovium samples were used to analyze the changed metabolites of moxibus-tion on RA rats by the GC-MS based metabolomics. Results:Treatment of moxibustion not only significantly increased the weight of CIA rats,reduced the swelling of hind paw,arthritic scores,IL-1β,TNF-a but also improved histopathological evaluation in right ankle joint samples.Sixteen significantly altered metabolites were found in RA rats as potential biomarkers of arthritis.Thirteen metabolites,significantly adjusted by moxibustion to help relieve arthri-tis,were selected out as biomarkers of antiarthritic mechanism of moxibustion,which were mainly in-volved in phenylalanine,tyrosine and tryptophan biosynthesis,glycine,serine and threonine metabolism,phenylalanine metabolism,alanine,aspartate and glutamate metabolism,glyoxylate and dicarboxylate metabolism and aminoacyl-tRNA biosynthesis. Conclusions:We have indicated moxibustion treatment is able to resist inflammation in CIA rats ef-fectively.Using GC-MS metabolomics technique,we detect novel metabolites in the moxibustion an-tiarthritic process,which may aid in advanced understanding of arthritis and therapeutic mechanism of moxibustion.