Fig 4. Delayed efficacy of eupatilin in MIA-induced OA.

Rats were injected with 3 mg of monosodium iodoacetate (MIA) in the right knee. Eupatilin was administered orally daily for 14 days after MIA injection. (A) The knee joints from the OA rats treated with either eupatilin or vehicle control were stained with HE, Safranin O, and toluidine blue. The joint lesions were graded on a scale of 0–13 using the modified Mankin scoring system, giving a combined score for cartilage structure, cellular abnormalities, and matrix staining. The data are expressed as means ± SEM for six animals per group. (B) Osteoclasts were measured in the subchondral bone region. *P< 0.05, and **P< 0.01 compared with the vehicle-treated OA animals.