| Objective To study the effect and mechanism of pulsed electromagnetic field (PEMF) on ovariectomized osteoporosis (OVX-OP) rats. Methods Six-month-old female SD rats were randomly divided into four groups: sham operated group (S group), model group (M group, bilateral ovariectomy), estrogen treatment group (E group, estrogen treatment based on M group) and PEMF group (PEMF treatment based on M group), with 10 rats in each group, and they were treated for 8 weeks after 8 weeks of feeding. The weight of rats in each group before and after treatment was weighed; the bone mineral density of right humerus was measured by dual energy X-ray experimental animal bone densitometer. At the end of treatment, the static bone morphometry of 1/3 upper tibia was measured by the semi-automatic digital image analyzer; and Western blotting (WB) was used to detect the protein expression of Smad ubiquitin regulatory factor 1 (Smurf1) in bone tissue of rats in each group. Results Compared with S group, the mental state of M group, E group and PEMF group was not good, and there was no abnormality in diet, activity and defecation. Before treatment, compared with S group, the weight of rats in M group, E group and PEMF group increased significantly (P<0.05)，while the bone mineral density decreased significantly (P<0.05); while after treatment, the weight of rats in E group and PEMF group decreased significantly (P<0.05)，and the bone mineral density increased significantly (P<0.05); compared with S group, the bone mineral density, BV/TV, Tb.N, and Tb.Th in M group decreased significantly (P<0.05), while the weight of rats, Tb.Sp and the protein level of Smurf1 increased significantly (P<0.05); compared with group M, the bone mineral density, BV/TV, Tb.N and Tb.Th in E group and PEMF group increased significantly (P<0.05), while the weight of rats, Tb.Sp and the protein level of Smurf1 decreased significantly (P<0.05); There was no significant difference between E group and PEMF group (P>0.05). Conclusions PEMF may improve bone morphology by up-regulating the expression of Smurf1 protein, and then play the role of anti osteoporosis, which may be related to the down-regulation of Smurf1 protein expression. |