Effects of Pulsed Electromagnetic Fields on the mRNA Expression of RANK and CAII in Ovariectomized Rat Osteoclast-Like Cell

This study was designed to determine the effects of pulsed electromagnetic fields (PEMF) on the mRNA expression of the receptor activator of NF-kappa-B (RANK) and carbonic anhydrase II (CA II) in ovariectomized rat osteoclast-like cells. Marrow cells were harvested from femora and tibiae of rats, from which the ovaries had been totally excised, and cultured in 6-well chamber slides. After 1 day of incubation, the marrow cells were exposed to PEMF for 3 days with 3.8 mT, 8 Hz, and 40 min per day. Osteoclast-like cells were confirmed by both tartrate resistant acid phosphatase (TRAP) stain and bone resorption assay. The expression of RANK and CA II mRNA was determined with real-time fluorescent-nested quantitative polymerase chain reaction. Compared with the sham group, the level of serum estradiol in the ovariectomized group was significantly decreased (p < 0.05). The numbers of multinucleated, TRAP-positive osteoclast-like cells and resorption pits formed were observed. In invitro study, the expression of RANK and CA If were measured in sham, ovariectomized without PEMF, and ovariectomized with PEMF treatment. Compared with the ovariectomized (PEMF) experimental group and sham group, CA II mRNA expression was significantly increased in the ovariectomized control group (p < 0.05, 0.01, respectively). Compared with the sham group, RANK mRNA expression was significantly increased in the ovariectomized control group (p < 0.05). These data suggest that PEMF could regulate the expression of RANK and CA II mRNA in the marrow culture system.