Third International Meeting on the Molecular Mechanisms of Metal Toxicity and Carcinogenicity

Corresponding Author Fax : 806–742–2712 Email: x le fk@ttac s.ttu.edu RHEUMATOID arthritis (RA) is character ized by an abnorm al cellular and cytokine in filtration of in flam ed join ts . Th is s tudy addre sses a previously unrecogn ized in te raction be tw een neutrophilic-m yeloperox idase (MPO) and m acrophages (Mø) w h ich could ex plain th e perpe tuation of in flam m ation associated w ith RA. A m onoarticular arth ritis w as in duced in fe m ale Lew is rats by in jection of s treptococcal ce ll w all ex tracts (PG-APS). After sw elling and e rythem a subs ided, joints were re-injected w ith one of the fo llow ing: porcin e MPO or partially inactivated MPO (iMPO). In jection w ith eithe r MPO or iMPO in duced a ‘flare ’ of ex perim ental RA. Blocking th e Mø-m annose receptor by m annans, ablated ex acerbation of dis ease. These re sults in dicate that MPO or iMPO can play a pivotal role in th e p erp e tuation but no t initiation of th is RA m odel.