title: Pulsed electromagnetic fields protect the balance between adipogenesis and osteogenesis on steroid-induced osteonecrosis of femoral head at the pre-collapse stage in rats.
abstract: This study was designed to investigate the effects of pulsed electromagnetic fields (PEMF) on the balance of adipogenesis and osteogenesis on steroid-induced osteonecrosis of the femoral head (OFH) in rats. Forty-two rats were divided into three groups: Steroid group (S, n = 16); Steroid + PEMF group (S + P, n = 16); and Control group (C, n = 10). For groups S and S + P, all rats were first intravenously given 10 µg/kg lipopolysaccharide on day 1, and then intramuscularly injected with 20 mg/kg methylprednisolone acetate on days 2, 3, and 4, with an interval of 24 h. After 4 weeks, the S + P group was treated with PEMF (4.5-ms square pulse, repeated at 15 Hz, with a peak of 1.2 mT) for 4 h a day for the next 8 weeks. Group S was not exposed to PEMF. Group C was chosen as the control group, without steroid use and exposure to PEMF. After 8 weeks of treatment, the histological changes, and mRNA and protein expressions of PPAR-γ2 and Runx2 were measured and analyzed. Compared with the S group, lower incidence of osteonecrosis (31% vs. 69%, P < 0.05) and empty osteocyte lacuna rate (36.16 ± 15.34 vs. 59.55 ± 21.70, P < 0.01) was observed in the S + P group. Furthermore, PEMF suppressed the expressions of PPAR-γ2 and improved the expressions of Runx2 in the femoral head (P < 0.05). All data suggest that PEMF is an effective physiotherapy in the treatment of steroid-induced ONFH, and the possible underlying mechanisms include protecting the balance between adipogenesis and osteogenesis.
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, People's Republic of, China.
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Li
authors.forename: Sen
authors.initials: S
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Peng
authors.forename: Jian-Lin
authors.initials: JL
authors.lastname: Zhou
authors.forename: Hong-Song
authors.initials: HS
authors.lastname: Fang
mesh_terms: D050156:Adipogenesis; D000818:Animals; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D004574:Electromagnetic Fields; D005270:Femur Head / Q000473:pathology*; D005271:Femur Head Necrosis / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology* / Q000628:therapy*; D007668:Kidney / Q000473:pathology; D008070:Lipopolysaccharides; D008099:Liver / Q000473:pathology; D055909:Magnetic Field Therapy / Q000295:instrumentation / Q000379:methods; D008297:Male; D008775:Methylprednisolone / Q000031:analogs & derivatives; D000077555:Methylprednisolone Acetate; D010011:Osteocytes / Q000473:pathology / Q000502:physiology; D010012:Osteogenesis; D047495:PPAR gamma / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D008070:Lipopolysaccharides; D047495:PPAR gamma; D012333:RNA, Messenger; C493717:Runx2 protein, rat; D000077555:Methylprednisolone Acetate; D008775:Methylprednisolone
keywords: Runt-related transcription factor 2 (Runx2); glucocorticoids; ischemia necrosis of femoral head; peroxisome proliferator-activated receptor-γ2 (PPAR-γ2); pulsed electromagnetic fields simulation