(332) Protein levels of high mobility group box 1 and receptor for advanced glycation end products are higher in young adult rats with arthritis compared to juvenile rats with arthritis

Abstract

Arthritis is among the most common chronic diseases in both children and adults. Arthritis is a potentially disabling disease that can result in ongoing pain and inflammation of the affected joints. While JIA is considered similar to adult rheumatoid arthritis (RA), it is also widely accepted that many differences exist between children and adults. Collagen induced arthritis (CIA) has long been used as a model of adult RA and inflammatory pain and recently, we have demonstrated that CIA in juvenile animals is a suitable model of juvenile arthritis. This research examines changes in protein expression levels of the pro-inflammatory cytokine high mobility group box 1 (HMGB1) and its receptor RAGE (receptor for advanced glycation end products) in juvenile and young adult rats two weeks following the onset of collagen-induced arthritis (CIA). Juvenile (5 week old) and young adult (13 week old) rats were injected at the base of the tail with bovine type II collagen. This resulted in the development of a monophasic polyarthritis in the hindpaws. Naïve age-matched rats were included as controls. DRG were sectioned and processed by immunohistochemistry to detect levels of HMGB1 and RAGE. In the naïve state, juvenile rats have lower levels of both HMGB1 and RAGE present in the DRG compared to naïve young adult rats. Young adult rats with CIA were found to express noticeable higher levels of HMGB1 and dramatically higher levels of RAGE compared to juvenile rats with CIA. This provides evidence young adult rats may be predisposed to experiencing higher levels of inflammation and pain following CIA than juvenile rats. This research is supported by the University of Saskatchewan, Pediatric Rheumatic Disease Laboratory, Children’s Hospital Foundation of Saskatchewan. TDW-G is supported by Pain in Child Health and Pediatric Rheumatic Disease Laboratory. Arthritis is among the most common chronic diseases in both children and adults. Arthritis is a potentially disabling disease that can result in ongoing pain and inflammation of the affected joints. While JIA is considered similar to adult rheumatoid arthritis (RA), it is also widely accepted that many differences exist between children and adults. Collagen induced arthritis (CIA) has long been used as a model of adult RA and inflammatory pain and recently, we have demonstrated that CIA in juvenile animals is a suitable model of juvenile arthritis. This research examines changes in protein expression levels of the pro-inflammatory cytokine high mobility group box 1 (HMGB1) and its receptor RAGE (receptor for advanced glycation end products) in juvenile and young adult rats two weeks following the onset of collagen-induced arthritis (CIA). Juvenile (5 week old) and young adult (13 week old) rats were injected at the base of the tail with bovine type II collagen. This resulted in the development of a monophasic polyarthritis in the hindpaws. Naïve age-matched rats were included as controls. DRG were sectioned and processed by immunohistochemistry to detect levels of HMGB1 and RAGE. In the naïve state, juvenile rats have lower levels of both HMGB1 and RAGE present in the DRG compared to naïve young adult rats. Young adult rats with CIA were found to express noticeable higher levels of HMGB1 and dramatically higher levels of RAGE compared to juvenile rats with CIA. This provides evidence young adult rats may be predisposed to experiencing higher levels of inflammation and pain following CIA than juvenile rats. This research is supported by the University of Saskatchewan, Pediatric Rheumatic Disease Laboratory, Children’s Hospital Foundation of Saskatchewan. TDW-G is supported by Pain in Child Health and Pediatric Rheumatic Disease Laboratory.