Effect of etidronate disodium on different skeletal sites in orchiectomized rats / 中国组织工程研究

ABSTRACT

BACKGROUND: Prevention of male osteoporosis is attracting more and more attention. OBJECTIVE: To study the effect of etidronate disodium on different skeletal sites by using bone histomorphometry through establishing a castrated rat model of osteoporosis. DESIGN, TIME AND SETTING: A completely randomized grouping controlled animal experiment was performed in the Animal Experimental Center and Department of Bone Biology Laboratory, Guangdong Medical College between October 2002 and September 2006. MATERIALS Forty 3.5-month-old male Sprague Dawley rats, weighing (299+_22) g, were selected. Etidronate disodium was produced by Chengdu Chemical Pharmaceutical Factory with the batch number of 970101. Methyltestosterone was produced by Guangzhou Pharmaceutical Jacob with the batch number of 990701. METHODS: Rats were randomly divided into five groups control group, sham operation group, castration group, castration with methyltestosterone group and castration with etidronate disodium group, eight rats in each group. Rats in the control group were sacrificed at the beginning of the study. Rats in the sham operation group underwent skin incision to expose the testis, but not removed. The remaining rats were treated to remove the testis by the method reported in the literature. Rats in the sham operation group and castration group were given normal saline, rats in the castration with methyltestosterone group were given methyltestosterone at 1.8mg/kg/d, rats in the castration with etidronate disodium group were given etidronate disodium at 36mg/kg/d. All of the rats were treated with intragastric administration at 5mL/kg for 90 days. MAIN OUTCOME MEASURES: Bone histomorphometric analysis of the proximal tibial metaphysis (PTM), tibial shaft (Tx) and the fifth lumbar vertebral body (LVB) were performed in undecalcified sections. RESULTS: Compared with the sham operation group, trabecular area percentage (%Tb.Ar), trabecular number (Tb.N) or trabecular thickness (Tb.Th) of PTM and LVB in the castration group were decreased (P < 0.05 and 0.01 ), while trabecular separation (Tb.Sp), percent labeled perimeter (%L.Pm), bone formation rate (BFR/BV) and osteoclast number per mm (Oc.N) were increased (P < 0.05 and 0.01 ). Tb.Ar of PTM and LVB were increased both in the etidronate disodium group and in the methyltestosterone group compared to those of the castration group, while bone formation indices and bone resorption perimeter were decreased. There was no significant difference between the etidronate disodium and methyltestosterone groups, and no significant change was in Tx in all groups. CONCLUSION: Etidronate disodium can prevent the cancellous bone loss of PTM and LVB in castrated rats, but has no effects on the cortical bone of Tx.