Background The management of the chronic inflammatory rheumatisms has dramatically evolved in the last decade with a concept of “treat to target”. The theory of a window of opportunity with more beneficial effects of an early intensive treatment is supported by several evidences. The positive impact of an early treatment with a TNFα blocker is expected but the place and the interest of non-steroidal anti-inflammatory treatments (NSAIDs) and glucocorticoids is not clear.
Objectives The aim of this study was to evaluate the radiological outcomes after an early treatment during 21 days by Etanercept, or Naproxene, or Celecoxib, or Prednisone, or Diclofenac or Methotrexate in adjuvant induced arthritis in rats.
Methods Adjuvant-induced arthritis (AIA) was induced in 6 weeks old male Lewis rats by injection of Mycobacterium butyricum in adjuvant at the basis of the tail. At the onset of arthritis, rats were daily treated with Naproxene (10 mg/kg/d i.p), or Diclofenac (5mg/kg i.p twice a day), or Celecoxib (3 mg/kg/d i.p) or Prednisone (10 mg/kg/d i.p), or Etanercept (10 mg/kg/3 days, s.c.), or Methotrexate (1mg/kg/3 days, s.c.), or saline solution (Vehicle), for 21 days. Arthritic score was daily monitored. At the end of treatment, paws' radiological exam was performed with a BMA High Resolution Digital X Ray (40mV, 10mA). A score of 0 to 20 was determined for each paw using a grading scale modified from Ackerman et al (1979).
Results Compared to the Vehicle, all treatments significantly reduced (p<0.001) arthritic score with a reduction of the arthritic score evaluated between 40% (for methotrexate) and 70% (for diclofenac) (figure 1. Compared to the vehicle, the radiographic score was improved by Naproxene, Diclofenac, Celecoxib, Glucocorticoids, Etanercept (p<0.001) but not by methotrexate. Compared to Etanercept, Naproxene and diclofenac showed less radiological structural changes (p<0.01) (figure 2).
Conclusions Our study demonstrates for the first time that an early treatment with NSAIDs, excluding COX2 selective inhibitor, is more beneficial than Etanercept on the radiological damages in adjuvant induced arthritis. The close efficacy of all drugs on the arthritis score suggests that the beneficial impact of NSAID is not only driven by their impact on the systemic inflammation. NSAIDs should be used during the window of opportunity.
Disclosure of Interest None declared