| Objective Hartley guinea pigs is a widely used spontaneous model of osteoarthritis.Calcitonin (CT) is a recognized inhibitor of bone resorption, which inhibits osteoclastactivity by binding with CT receptor on osteoclasts, and its primary role is to regulateblood calcium levels. CT has long been used for the treatment of osteoporosis, and alsohas a protective effect on cartilage, but its effect on spontaneous osteoarthritis in guineapigs rarely reported. This study investigated the protection effects of CT on articularcartilage and subchondral bone in guinea pigs with spontaneous arthritis.Methods Thirty-six1-month-old guinea pigs were divided into six groups:24guineapigs were treated by normal saline and sacrificed at1(G1),3(G2),6(G3) and9(G5)months of age; the other12received CT (9IU/kg/d,5days weekly) from3months of age,and were sacrificed at6(G4) and9(G6) months. A histomorphometric study was based onthe morphological changes of the articular cartilage and stained with Massson and VanGieson and graded by Mankin’s scale. Immunohistochemistry analyses ofglycosaminoglycans and Interleukin-1in the cartilage.Results1General observation and histological analysis showed knee-joint in Group1seems normal, G2group had mild arthritis, G3group of arthritis is more obvious, G5group of arthritic disease seriously. Articular cartilage Mankin score results and arthritissymptoms of G4group and G6group are significantly better than G3group and G5group (P <0.05).2Bone mineral density (BMD) of right distal femoras and femoracondyles of G4group and G6group ware significantly higher than G5group and G3group(P <0.05) respectively. When compared with the age-matched control groups, CTtreatment improved Subchondral bone performance.3Immunohistochemical staining ofthe joint observation that articular cartilage GAG is gradually decreased while IL-1isgradually increased in guinea pig OA progresses, compared with the same period in thecontrol group, the expression of GAG significantly increase (P <0.05), IL-1expressionwas significantly decreased (P <0.05) in CT treated group.Conclusion Hartley guinea pigs appeared OA at3months of age and was more severewith increasing age. Calcitonin can inhibit inflammation of articular cartilage by reducing the expression of IL-1and promote the synthesis of GAG to prevent the degradation ofcartilage matrix, and improve the function of subchondral bone. CT could be used forconservative treatment of osteoarthritis. |
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