Histological grading of the knee sections for the total joint inflammation using a scale ranging from 0 to 4. (-) indicates groups without a magnet, and (+) indicates groups with a magnet. Results are expressed as individual values, and the horizontal line represents the mean (n = 5 mice per group). **P < 0.05 was considered significant. The histological analysis shows that the complete microparticles induced a significant inflammation reduction compared with the positive controls. The influence of the magnet on the inflammation score of the complete microparticle group is not significant. DXM, dexamethasone 21-acetate; mBSA, methyl bovine serum albumin; PBS, phosphate-buffered saline; SPION, superparamagnetic iron oxide nanoparticle.