Comparison of chronic effects of intra-articular tenoxicam, diclofenac and methylprednisolon on healthy rats

Lyophilized drug manufacturing and intra-articular (IA) applications have increased to address gastrointestinal side effects resulting from chronic treatment with non-steroidal anti-inflammatory drugs (NSAIDs) for degenerative joint disease. Accordingly, we histologically examined joint and stomach tissues from rats to determine and compare the effects of long-term treatment with an IA corticosteroid (methylprednisolone acetate), lyophilized NSAID (tenoxicam), and non-lyophilized NSAID (diclofenac) following application to the knee joint.One hundred Wistar albino rats were divided into 4 groups of 25 rats: control, methylprednisolone, tenoxicam, and diclofenac. Ten IA injections were administered at 1-week intervals. Rats were sacrificed at 48 h and 1, 2, 4, and 8 weeks after the tenth injection. Histomorphologically, knee joint samples were examined for osteoarthritic changes and stomach tissue samples for gastric changes.Unlike methylprednisolone, diclofenac and tenoxicam caused increased fibrosis and fibroblast production; furthermore, chronic methylprednisolone use had no negative effects on the synovium or cartilage.Chronic tenoxicam and diclofenac use affects joints more negatively than chronic steroid treatment.