title: Arthritic disease is more severe in older rats in a kaolin/carrageenan-induced arthritis model.
abstract: This study examined in an arthritis animal model whether elderly onset rheumatoid arthritis (EORA) is a more severe disease than younger onset rheumatoid arthritis. Arthritis was induced by injecting 5% kaolin/carrageenan into the left tibiotarsal ankles of 18-month-old and 4-week-old rats. Various parameters were measured to evaluate the arthritic progression of kaolin/carrageenan-induced arthritis in the rats. Immunohistochemical staining of arthritic joints was performed to determine the degree of inflammation in old and young rats. Measurements of ankle volume and thickness, arthritic index, number of squeaks, and the paw pressure test showed the 18-month-old rats had more severe disease than the young rats in a kaolin/carrageenan-induced arthritis model. The degree of inflammation and MMP-1 expression of arthritic joints in old rats was significantly higher than that of young rats based on histological evaluation with hematoxylin and eosin (H&E) staining and immunochemistry. More severe disease symptoms were found in old rats with EORA, but the molecular mechanisms still remain to be elucidated. Understanding the molecular mechanisms will be helpful to develop clinical protocols to efficiently treat patients with EORA, which is difficult to control with current protocols.
authors.affiliation: East-West Bone and Joint Research Institute, Kyung Hee University Hospital at Gangdong, Kyung Hee University, 149 Sangil-dong, Gangdong-gu, Seoul 134-727, Republic of Korea. labrea46@yahoo.co.kr
authors.forename: Kyoung Soo
authors.initials: KS
authors.lastname: Kim
authors.forename: Myung-Hwan
authors.initials: MH
authors.lastname: Kim
authors.forename: Mijung
authors.initials: M
authors.lastname: Yeom
authors.forename: Hyun Mi
authors.initials: HM
authors.lastname: Choi
authors.forename: Hyung-In
authors.initials: HI
authors.lastname: Yang
authors.forename: Myung Chul
authors.initials: MC
authors.lastname: Yoo
authors.forename: Dae-Hyun
authors.initials: DH
authors.lastname: Hahm
mesh_terms: D000179:Acrylates; D000367:Age Factors; D000818:Animals; D001169:Arthritis, Experimental / Q000378:metabolism / Q000473:pathology*; D002351:Carrageenan; D007249:Inflammation / Q000378:metabolism / Q000473:pathology*; D007596:Joints / Q000378:metabolism / Q000473:pathology*; D007616:Kaolin; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D010647:Phenyl Ethers; D051381:Rats; D017207:Rats, Sprague-Dawley; D012720:Severity of Illness Index
chemical_list: D000179:Acrylates; C087671:MA 12; D010647:Phenyl Ethers; D007616:Kaolin; D002351:Carrageenan; D020781:Matrix Metalloproteinase 1