[Effect of low frequency pulsed electromagnetic fields on lumbar bone histomorphometry in ovariectomized osteoporosis rats].

Abstract

OBJECTIVE:

To investigate the changes of lumbar bone histomorphometry after exposure to low frequency pulsed electromagnetic fields (PEMFs), and to further understand the effect of PEMFs on osteoporosis (OP) in ovariectomized OP rats.

METHODS:

Sixty-six 3-month-old Sprague Dawley rats were randomly divided into 4 groups: group A (n = 12), group B (n = 12), group C (n = 12), and group D (n = 30). In group A, the ovaries were not resected as sham-ovariectomy; in groups B, C, and D, the ovaries were resected. At 12 weeks after ovariectomy, the rats were exposed to PEMFs at 8 Hz, 3.8 mT, and 40 minutes/day for 30 days in group B; the rats were administered with premarin [0.065 mg/(kg x d) by gavage for 30 days] in group C; in group D, the rats were housed as ovariectomy control. The hair and activity of rats were observed; the levels of serum estradiol were determined. At 30 days after intervention, all rats were sacrificed to harvest the L4 vertebrae for bone histomorphometry.

RESULTS:

General observation showed hair loss and decreased activity in group D, and no abnormal appearances in groups A, B, and C. The level of serum estradiol in group A was significantly higher than that in group D [(54.93 +/- 23.52) pg/mL vs. (31.99 +/- 23.45) pg/mL] (t = 2.345, P = 0.029). Histological observation showed thinness of sclerotin, bigger medullary cavity, and sparse and thinner bone trabecula in group D; uniform bone trabecula with no breakage in groups A, B, and C at 30 days after intervention. The ratio of trabecular bone area in group B was significantly higher than that in group D (P < 0.05); it was higher than that in groups A and C, showing no significant difference (P > 0.05). The trabecular thickness in group B was significantly higher than that in group D (P < 0.05), but it was lower than that in groups A and C, showing no significant difference (P > 0.05). The trabecular number in group B was significantly lower than that in group D (P < 0.05), but it was higher than that in groups A and C, showing no significant difference (P > 0.05). The trabecular separation in group B was higher than that in group D and lower than that in groups A and C, showing no significant difference (P > 0.05).

CONCLUSION:

PEMFs at 8 Hz and 3.8 mT can significantly improve the character of bone microstructure in ovariectomized OP rats, increase the ratio of bone trabecular area and trabecular thickness, and decrease the trabecular number.

• Authors: Jian Chen, Liqun Huang, Yujun Hu, Chengqi He
• Journal: Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery (Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi) Vol. 25 Issue 12 Pg. 1455-8 (Dec 2011) ISSN: 1002-1892 [Print] China
• PMID: 22242344 (Publication Type: English Abstract, Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Animals
• Bone Density
• Disease Models, Animal
• Electromagnetic Fields
• Female
• Lumbar Vertebrae (pathology)
• Osteoporosis (etiology, pathology)
• Ovariectomy
• Rats
• Rats, Sprague-Dawley