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Pulsed electromagnetic fields protect the balance between adipogenesis and osteogenesis on steroid‐induced osteonecrosis of femoral head at the pre‐collapse stage in rats
Author(s) -
Li JianPing,
Chen Sen,
Peng Hao,
Zhou JianLin,
Fang HongSong
Publication year - 2014
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.21833
Subject(s) - methylprednisolone , femoral head , adipogenesis , medicine , osteocyte , endocrinology , steroid , chemistry , surgery , adipose tissue , osteoblast , in vitro , hormone , biochemistry
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. Bioelectromagnetics. 35:170–180, 2014. © 2014 Wiley Periodicals, Inc.