title: Expression of peptidylarginine deiminase 4 and protein tyrosine phosphatase nonreceptor type 22 in the synovium of collagen-induced arthritis rats.
abstract: OBJECTIVE
  To study the expression level of peptidylarginine deiminase 4 (PADI4) and protein tyrosine phosphatase nonreceptor type 22 (PTPN22) in the synovium of rat model of collagen-induced arthritis, and to explore their possible therapeutic role in rheumatoid arthritis.
  
  
  METHODS
  Thirty-two female Wistar rats weighing 100±20 g were randomly assigned into 3-week collagen-induced arthritis (CIA) model group (n=8), 4-week CIA model group (n=8), 6-week CIA model group (n=8), and the control group (n=8). The body weight changes of each group were recorded. The expression levels of PADI4 and PTPN22 were detected and compared by the methods of immunohistochemical staining and Western blot.
  
  
  RESULTS
  Arthritis of rat began to form 14 days after sensitization and the joint swelling reached peak at 28 days. The weights of the rats slowly grew both in CIA model groups and the control group. Immunohistochemical staining results showed that the positive expression of PADI4 and PTPN22 was mainly located in cartilage peripheral mononuclear cells, the cytoplasm of infiltrated cells, and bone marrow cavity. There were significant differences in the optical density of PADI4 and PTPN22 among CIA model groups and the control group (PADI4, 0.2898±0.012, 0.2982±0.022, 0.2974±0.031, 0.2530±0.013 in 3-week CIA model, 4-week CIA model, 6-week CIA model and control groups; PTPN22, 0.2723±0.004, 0.2781±0.010, 0.2767±0.008, 0.2422±0.019; all P <0.05). The expression bands of PADI4 were observed in Western blot 3 weeks after initial immunization, the thickest in the 4th week, and decreased in the 6th week. The expression bands of PTPN2 were observed at all the time points, with no obvious time-dependent trend.
  
  
  CONCLUSIONS
  PADI4 and PTPN22 are obviously correlated with CIA in rat model. PADI4 is expressed at early stage of the disease, while the expression of PTPN22 sustains throughout the course.
authors.affiliation: Department of Rheumatology, Shengjing Hospital of China Medical University, Shenyang 110001, China.
authors.forename: Yan-Bing
authors.initials: YB
authors.lastname: Xu
authors.affiliation: Department of Rheumatology, Shengjing Hospital of China Medical University, Shenyang 110001, China.
authors.forename: Nai-Zhi
authors.initials: NZ
authors.lastname: Wang
authors.affiliation: Department of Rheumatology, Shengjing Hospital of China Medical University, Shenyang 110001, China.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Yang
authors.affiliation: Department of Rheumatology, Shengjing Hospital of China Medical University, Shenyang 110001, China.
authors.forename: Hua-Dong
authors.initials: HD
authors.lastname: Cui
authors.affiliation: Department of Rheumatology, Shengjing Hospital of China Medical University, Shenyang 110001, China.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Xue
authors.affiliation: Department of Rheumatology, Shengjing Hospital of China Medical University, Shenyang 110001, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000201:enzymology / Q000378:metabolism*; D015153:Blotting, Western; D003094:Collagen / Q000008:administration & dosage*; D005260:Female; D006867:Hydrolases / Q000378:metabolism*; D007150:Immunohistochemistry; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22 / Q000378:metabolism*; D000080002:Protein-Arginine Deiminase Type 4; D000076342:Protein-Arginine Deiminases; D051381:Rats; D017208:Rats, Wistar; D013583:Synovial Membrane / Q000201:enzymology / Q000378:metabolism*
chemical_list: D003094:Collagen; D006867:Hydrolases; C000590795:PTPN22 protein, rat; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22; D000080002:Protein-Arginine Deiminase Type 4; D000076342:Protein-Arginine Deiminases; C000590797:peptidylarginine deiminase 4, rat