Effects of genistein on bone mineralization and osteoporosis in ovariectomized rats / 中国组织工程研究

ABSTRACT

BACKGROUND: Genistein is the main component of phytoestrogen soy isoflavone and its structure is similar to estrogen,which suggests that it might prevent or delay osteoporosis. Research on the effects of genistein on bone mineralization and calcium(Ca), phosphor(P), zinc(Zn) and magnesium (Mg) in ovariectomized rats are rare.OBJECTIVE: To investigate the effects of genistein on bone mineralization and Ca,P,Zn and Mg in ovariectomized rats to provide a theoretical gist for the prevention of osteoporosis by genistein.DESIGN: A controlled experiment based on experimental animals.SETTING: Department of Nutrition,General Hospital of Chinese PLA.MATERIALS The study was conducted in the Institute of Hygiene and Environmental Medicine,Academy of Military Medical Sciences of PLA between February and June 2003. Ten-week old female Wistar rats [certification number (military medical animal) D98014] with a body mass of(170±20) g were selected.INTERVENTIONS: Experimental animals were fed with normal feeding for 6 weeks and then the feeding was changed to AIN-93 compound. Animals were then randomly divided into ovariectomized group (n=40) and sham-operation group(n=7) based on bodyweight after 5 days. Ovariectomized group received ovariectomy and sham-operation group only received abdominal incision. After 5 days of recovery,the ovariectomized group was further randomly divided into 5 subgroups with 8 rats each including ovariectomized control subgroup,estrogen subgroup [diethylstilbestrol 20 μg/(kg · d)],genistein Ⅰ,Ⅱ,or Ⅲ subgroup[dose of 25,50 or 100 mg/(kg · d)]. After 3months of feeding,6 rats were randomly selected from each group for the detection of bone density and corresponding bone hismorphometric indicators.MAIN OUTCOME MEASURES: Bone density,corresponding parameters of bone mineralization,Ca,P,Zn and Mg contents in bone of mice in each group RESULTS: After ovariectomy,femoral bone density decreased [(0. 247± 0.007) g/cm2],mean osteoid width increased[(7. 04 ±0. 32)μm],bone mineralization delayed [(4.96±0.99) days],osteoid maturity prolonged [(26.99±7.70) days],and Ca[ (251.11± 5.31) mg/g],P[(115.08± 3.78) mg/g],Zn[ (299.69±37.1)μg/g] and Mg[(4. 32±0. 12) μg/g]were all significantly different from that of sham-operation group(P<0.05).After the application of genistein,femoral bone density had a tendency of improvement[ (0. 250±0. 007) g/cm2],mean osteoid width narrowed[ (4. 97±0.77) μm],bone mineralization delayed time[ (3.18±0.69) days] and osteoid maturity time[(14.53 ±3.84) days] shortened, contents of Ca [(270.00±5.65) mg/g],P[(124.25±2.37) mg/g] andMg[(4.61±0. 08) μg/g]elevated while Zn content had no significant changes.CONCLUSION: Genistein promotes osteoid mineralization,reduces the loss of Ca, P and Mg in the bone and prevent the generation of osteoporosis in unsexed rats