This study investigated the effects of pulsed electromagnetic fields (PEMFs) on proteoglycan (PG) metabolism of human articular cartilage explants from patients with osteoarthritis (OA). Human cartilage explants, recovered from lateral and medial femoral condyles, were classified according to the International Cartilage Repair Society (ICRS) and graded based on Outerbridge scores. Explants cultured in the absence and presence of IL-1β were treated with PEMF (1.5 mT, 75 Hz) or IGF-I alone or in combination for 1 and 7 days. PG synthesis and release were determined. Results showed that explants derived from lateral and medial condyles scored OA grades I and III, respectively. In OA grade I explants, after 7 days exposure, PEMF and IGF-I significantly increased (35) S-sulfate incorporation 49% and 53%, respectively, compared to control, and counteracted the inhibitory effect of IL 1β (0.01 ng/ml). The combined exposure to PEMF and IGF-I was additive in all conditions. Similar results were obtained in OA grade III cartilage explants. In conclusion, PEMF and IGF-I augment cartilage explant anabolic activities, increase PG synthesis, and counteract the catabolic activity of IL-1β in OA grades I and III. We hypothesize that both IGF-I and PEMF have chondroprotective effects on human articular cartilage, particularly in early stages of OA.
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