Jiale Shao1,2, Zhizhong Li2, Jian Zhou1, Kai Li1, Rong Qin1, Keming Chen1. 1. Institute of Orthopedic Research, the 940th Hospital of Joint Logistics Support Force of People's Liberation Army, Lanzhou 730050, China. 2. School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China.
Abstract
OBJECTIVE: To investigate the effect of low-frequency pulsed electromagnetic fields (PEMF) on the maturation and mineralization of rat cranial osteoblasts in vitro and its relation to IGF-1R/NO signaling pathway. METHODS: The rat osteoblasts were isolated and cultured in vitro and randomly divided into blank control group, PEMF group, GSK group (IGF-1R blocker) and PEMF+GSK group. The cells were treated with 50 Hz 0.6 mT PEMF for 1.5 h/d. After 3 d of PEMF treatment, the expressions of protein kinase (AKT), inducible nitric oxide synthase (iNOS) and cGMP-dependent protein kinase (PKG) were detected by Western blotting; on 6 d of PEMF treatment alkaline phosphatase (ALP) activity was determined; on 12 d of PEMF treatment the calcification nodule formation was demonstrated by Alizarin red staining. RESULTS: NO level was significantly increased in rat osteoblasts treated with 50 Hz 0.6 mT PEMF for 1.5 h/d. Western blot analysis showed that the expressions of AKT, iNOS and PKG protein in PEMF group were higher than those in the control group (all P<0.01); the ALP activity was increased(P<0.05), and the PEMF group had the largest area of Alizarin red staining (P<0.01). The expressions of AKT, iNOS and PKG protein in GSK group were lower than those in the control group; the ALP activity was decreased (P<0.05), and the GSK group had the least area of Alizarin red staining (P<0.01). The expressions of AKT, iNOS, PKG protein, the ALP activity and the area of Alizarin red staining in PEMF+GSK group were between PEMF group and GSK group. CONCLUSIONS: PEMF may enhance the maturation and mineralization of rat cranial osteoblasts in vitro through IGF-1R/NO signaling pathway.
OBJECTIVE: To investigate the effect of low-frequency pulsed electromagnetic fields (PEMF) on the maturation and mineralization of rat cranial osteoblasts in vitro and its relation to IGF-1R/NO signaling pathway. METHODS: The rat osteoblasts were isolated and cultured in vitro and randomly divided into blank control group, PEMF group, GSK group (IGF-1R blocker) and PEMF+GSK group. The cells were treated with 50 Hz 0.6 mT PEMF for 1.5 h/d. After 3 d of PEMF treatment, the expressions of protein kinase (AKT), inducible nitric oxide synthase (iNOS) and cGMP-dependent protein kinase (PKG) were detected by Western blotting; on 6 d of PEMF treatment alkaline phosphatase (ALP) activity was determined; on 12 d of PEMF treatment the calcification nodule formation was demonstrated by Alizarin red staining. RESULTS: NO level was significantly increased in rat osteoblasts treated with 50 Hz 0.6 mT PEMF for 1.5 h/d. Western blot analysis showed that the expressions of AKT, iNOS and PKG protein in PEMF group were higher than those in the control group (all P<0.01); the ALP activity was increased(P<0.05), and the PEMF group had the largest area of Alizarin red staining (P<0.01). The expressions of AKT, iNOS and PKG protein in GSK group were lower than those in the control group; the ALP activity was decreased (P<0.05), and the GSK group had the least area of Alizarin red staining (P<0.01). The expressions of AKT, iNOS, PKG protein, the ALP activity and the area of Alizarin red staining in PEMF+GSK group were between PEMF group and GSK group. CONCLUSIONS: PEMF may enhance the maturation and mineralization of rat cranial osteoblasts in vitro through IGF-1R/NO signaling pathway.