AIM: To investigate effect of bizhongxiao decoction (BZXD) on changes of protein in synovitis of rats with collagen-induced arthritis (CIA) and analyse mechanism of BZXD on treating rheumatoid arthritis (RA). METHODS: The experiment was completed in the Institute of Combined Traditional Chinese Medicine and Western Medicine, Xiangya Hospital of Central South University and Key Laboratory of Tumor Protein of Ministry of Public Health between May 2004 and February 2005. Totally 70 SD rats were divided randomly into 3 groups. Ten rats were regarded as normal group, and other 60 rats were modeled by type Ⅱ collagen and complete Freunds adjuvant. Successful rat models were selected and divided into BZXD group and model group. BZXD was consisted of 15 kinds of Chinese herbs such as baihuashe shecao 15g, zhongjiefeng 30 g, danshen 15 g, luoshiteng 20 g, gusuibu 15 g, yimi 30 g, etc., and fried with double distilled water for twice with 30 minutes each time. Then, liquid was mixed, filtered with G4 filter and concentrated in water bath at 60℃ with 116 g raw materials in each milliliter. Rats in BZXD group were perfused with 10 mL/kg BZXD (equal to 62.1 g raw materials) twice a day; rats in model group were perfused with 10 mL/kg saline twice a day; rats in normal group were drunk water freely. The total proteins of synovial tissue of rats in normal group, model group and BZXD group were separated by two-dimensional gel electrophoresis (2-DE), respectively. Then gels were stained by Coomassie brilliant blue, scanned by Image Scanner. Relative abundance of the protein spots was calculated by comparing spots density volume on the gel. The differentially expressed protein spots were identified by peptide mass fingerprint (PMF) based on matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and database searching, then some of them were validated by western blotting.
RESULTS: Among 70 rats, 7 were lost because of unsuccessful modeling, and totally 63 rats, 26 in BZXD group, 27 in model group and 10 in control group, entered the final analysis. ① Reproducible 2DE maps of synovial tissue were established in normal group, experimental arthritis model group and BZXD group respectively, the average spots of protein were 947±39, 994±41 and 1 031±52 respectively, and the match rates were 92%, 91% and 94.2%. ② Totally 55 protein spots were twice than expression of synovial tissue in normal group, experimental arthritis model group and BZXD group. This suggested that the functions of these proteins involved in metabolism, energy generation, transportation, anti-oxidation, signal transduction and protein folding etc. Then the different expressions of annexin 1 and aldolase A in normal group, experimental arthritis model group and BZXD group by western blotting were similar to those of proteomic results. CONCLUSION: Synovium of joint of rheumtoid arthritis is a complex process which is involved by multiple proteins. Histological analysis of proteins in synovium tissue is one of methods for screening related protein of lesion. Annexin 1 and aldolase A are related to CIA synovitis, and BZXD has a good effect on CIA by regulating protein expression of synovial tissue of rats.