Mediators of inflammation are down-regulated while apoptosis is up-regulated in rheumatoid arthritis synovial tissue by polymerized collagen

Abstract

Summary The aim of the study was to determine whether collagen-polyvinylpyrrolidone (collagen-PVP) modifies some proinflammatory responses in synovium cultures from rheumatoid arthritis (RA) patients. Synovium from 10 RA patients were cultured with or without 1% collagen-PVP. Tissues on the 3rd, 5th and 7th culture day were sectioned and stained by the Herovici technique. Total collagen and type I/III collagen ratios were evaluated by the Woessner micromethod and by interrupted gel electrophoresis, respectively. Collagenolytic activity was assessed by degradation of [3H]-collagen in supernatants. TIMP-1, IL-1β and TNF-α were determined in supernatants by ELISA, and the results were normalized by DNA concentration. IL-1β, TNF-α, IL-6, IL-8, MMP-1, TIMP-1, Cox-1, VCAM-1, ICAM-1 and Fas/APO95 expression was evaluated by immunohistochemistry. Apoptosis was detected by TUNEL technique. The histological analysis and electrophoresis revealed a 1·7-fold increase of type III collagen in a time-dependent fashion in collagen-PVP-treated cultures. Proinflammatory cytokines (IL-1β: 58 ± 9 versus 22 ± 10; TNF-α: 41 ± 6 versus 11 ± 3; IL-8: 59 ± 12 versus 29 ± 9; treated versus untreated), adhesion molecule (ICAM-1: 57 ± 11 versus 29 ± 15; VCAM-1: 49 ± 7 versus 21 ± 13; treated versus untreated) as well as Cox-1 (59 ± 10 versus 20 ± 3) expression was down-regulated in RA synovium treated. Meanwhile, TIMP-1 (36 ± 7 versus 57 ± 11) and Fas expression (20 ± 10 versus 55 ± 13) and apoptosis (14 ± 3 versus 55 ± 5) were up-regulated in treated cultures compared with controls. In supernatants, the collagenolytic activity, as well as IL-1β and TNF-α, levels were all down-regulated in treated cultures (two, three, fourfold, respectively). The addition of collagen-PVP to synovium-induced down-modulation of some inflammatory parameters and an increase in apoptosis of synovial cells. Perhaps this mechanism could contribute to inhibit outgrowth of pannus formation and to down-regulate inflammation of joints in patients with RA.