title: [Prophylactic administration of all-trans retinoic acid alleviates inflammation in rats with collagen-induced arthritis].
abstract: OBJECTIVE
  To investigate the effects of prophylactic administration of all-trans retinoic acid (ATRA) in relieving inflammation in a rat model of collagen-induced arthritis (CIA).
  
  
  METHODS
  Female Wistar rats (6 to 8 weeks old) were randomly divided into normal control group, solvent control group, and prophylactic ATRA treatment (0.05, 0.5, and 5 mg/kg) groups. All the rats except for those in normal control group were subjected to subcutaneous injection of type II collagen and incomplete Freund adjuvant in the tails to induce CIA, followed by injection on the following day with saline, corn oil or different doses of ATRA 3 times a week. The arthritis index (AI) scores, histological scores, serum levels of TNF-α, IL-17A, and IL-10, and expressions of proteases related with cartilage damage were evaluated.
  
  
  RESULTS
  On the 15th day after the primary immunization, the AI scores increased significantly in all but the normal control groups; the scores increased progressively in all the 3 ATRA groups but remained lower than that in the solvent control group, which was stable over time. The rats in the 3 ATRA groups showed obvious pathologies in the knee and ankle joints, but the semi-quantitative scores of pathology damage showed no significance among them. Compared with those in solvent control group, the serum IL-17A and TNF-α levels decreased, serum IL-10 level increased, and the expressions of ADAMT-4 and MMP-3 proteins decreased significantly in the knees in the 3 ATRA groups.
  
  
  CONCLUSIONS
  ATRA can reduce the production of TNF-α and IL-17A and increase the production of IL-10 to alleviate the inflammation in rats with CIA. ATRA may delay the progression of RA by correcting the imbalance of Th1/Th2 and Th17/Treg.
authors.affiliation: Department of Nutrition and Food Hygiene, West China School of Public Health, Sichuan University, Chengdu 610041, China. E-mail: zengxiang521@icloud.com.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zeng
authors.forename: Jing-Yan
authors.initials: JY
authors.lastname: Shan
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Yan-Hua
authors.initials: YH
authors.lastname: Ning
authors.forename: Xue-Jian
authors.initials: XJ
authors.lastname: Xie
authors.forename: Yu-Yan
authors.initials: YY
authors.lastname: Shen
authors.forename: Jie
authors.initials: J
authors.lastname: Song
authors.forename: Yun
authors.initials: Y
authors.lastname: Li
mesh_terms: D000071121:ADAMTS4 Protein / Q000378:metabolism; D000818:Animals; D001169:Arthritis, Experimental / Q000139:chemically induced / Q000188:drug therapy*; D024043:Collagen Type II; D005260:Female; D005620:Freund's Adjuvant; D007249:Inflammation / Q000188:drug therapy*; D016753:Interleukin-10 / Q000097:blood; D020381:Interleukin-17 / Q000097:blood; D008055:Lipids; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D058504:Th17 Cells / Q000276:immunology; D014212:Tretinoin / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D024043:Collagen Type II; D020381:Interleukin-17; D008055:Lipids; D014409:Tumor Necrosis Factor-alpha; C114843:incomplete Freund's adjuvant; D016753:Interleukin-10; D014212:Tretinoin; D005620:Freund's Adjuvant; D019278:Matrix Metalloproteinase 3; D000071121:ADAMTS4 Protein