去卵巢大鼠骨质疏松与17α-炔雌醇的预防作用

Osteoporosis in ovariectomized rats and the protective effects of 17 alpha-ethynylestradiol

目的:动态观察17α-炔雌醇用药4周和12周对去卵巢骨质疏松大鼠骨代谢的影响。方法:①实验于2002-6/2003-12在广东医学院附属医院骨生物学研究室完成。选用49只4月龄SD雌性大鼠随机分为7组:假手术4周组:假手术后,以蒸馏水2mL胃饲4周;去卵巢4周组:去卵巢手术后,以蒸馏水2mL胃饲4周;炔雌醇4周组:去卵巢术后,以30mg/(kg·d)炔雌醇2mL胃饲4周;假手术12周组:假手术后,以蒸馏水2mL胃饲12周;去卵巢12周组:行双侧卵巢摘除术后,以蒸馏水2mL胃饲12周;炔雌醇12周组:去卵巢术后,以30mg/(kg·d)炔雌醇2mL胃饲12周;炔雌醇用药/停药组:施行去卵巢手术并炔雌醇30mg/(kg·d)胃饲4周后停药,饲养至12周。②大鼠实验至相应时间后,用半自动图像数字化仪测量和计算左胫骨计量学参数(静态参数:骨小梁面积百分率、骨小梁宽度和骨小梁数量;动态参数:荧光周长百分率、矿化沉积率、单位骨小梁面积骨形成率、单位骨小梁周长骨形成率、破骨细胞数量、破骨细胞周长百分率)。③方差齐的各参数组间比较采用LSD方法进行单因素方差分析组间比较,方差不齐各参数,选用Dunnett'sT3方法进行单因素方差分析组间比较。结果:进入结果分析大鼠49只,每组7只。①骨小梁面积百分率和骨小梁数量:去卵巢4周组和炔雌醇4周组明显低于假手术4周组(P<0.05);炔雌醇4周组明显高于去卵巢4周组(P<0.05);去卵巢12周组、炔雌醇12周组和炔雌醇用药/停药组明显低于假手术12周组(P<0.05);炔雌醇12周组明显高于去卵巢12周组(P<0.05);炔雌醇用药/停药组明显低于炔雌醇12周组(P<0.05)。②所有骨计量学动态参数:去卵巢4,12周组明显高于假手术4和12周组(P<0.05);炔雌醇4和12周组明显低于去卵巢4,12周组(P<0.05);分别与假手术4和12周组相近;炔雌醇用药/停药组明显高于假手术12周组和炔雌醇12周组(P<0.05),与去卵巢12周组相近。③矿化沉积率、破骨细胞数量、破骨细胞周长百分率:假手术12周组明显低于假手术4周组(P<0.05)。④荧光周长百分率、骨形成率:去卵巢12周组明显低于去卵巢4周组(P<0.05)。⑤荧光周长百分率、矿化沉积率、骨形成率、破骨细胞周长百分率:炔雌醇12周组明显低于炔雌醇4周组(P<0.05)。结论:①炔雌醇用药4周和12周都可通过抑制骨吸收而预防去卵巢后骨丢失,使骨小梁面积百分率增加,但抑制骨吸收同时,有抑制骨形成的副作用。②炔雌醇停药后不能维持原疗效,骨小梁面积百分率还会下降,再发生骨丢失。

AIM： To dynamically observe the effects on the bone metabolism of ovariectomized rats with osteoporosis by the treatment of 17α- ethynylestradiol for 4 and 12 weeks. METHODS： ①The experiment was carried out in the Research Room of Bone Biology, Guangdong Medical College between June 2002 and December 2003. Forty-nine female SD rats aged d months were randomly divided into 7 groups： Sham-operated 4-week group： The rats were treated with gastric perfusion of distilled water （2 mL） for 4 weeks after sham operation; Ovariectomized 4-week group： The rats were treated with gastric perfusion of distilled water （2 mL） for 4 weeks after ovariectomy; Ethynylestradiol 4-week group： The rats were treated with gastric perfusion of ethynylestradiol （30 mg/kg per day） for 4 weeks after ovariectomy; Sham-operated 12-week group： The rats were treated with gastric perfusion of distilled water （2 mL） for 12 weeks after sham operation; Ovariectomized 12-week group： The rats were treated with gastric perfusion of distilled water （2 mL） for 12 weeks after bilateral ovariectomy; Ethynylestradiol 12-week group： The rats were treated with gastric perfusion of ethynylestradiol （30 mg/kg per day） for 12 weeks after ovariectomy; Ethynylestradiol on/off group： The rats were treated with gastric perfusion of ethynylestradiol （30 mg/kg per day） for 4 weeks after ovariectomy, and raised to 12 weeks after drug withdrawal. ② The semi-automatic image digital apparatus was used to measure and calculate left tibial metric indexes （static indexes： trabecular area percentage, trabecular width and trabecular number; dynamic indexes： fluorescent circumstance percentage, mineral appositional rate, bone formation rate of unit trabecular area and circumstances, number of osteoclasts, osteoclast circumstance percentage）. ③The indexes with homogenous variance were compared with the univariate analysis of variance by using the LSD methods among the groups, and those with heterogenous variance were compared with the univariate analysis of variance by using the Dunnett＇s T3 methods. RESULTS： All the 49 rats were involved in the analysis of results with 7 rats in each group. ①Trabecular area percentage and trabecular number： Those were obviously lower in the ovariectomized 4-week group and ethynylestradiol 4-week group than in the sham-operated 4-week group （P 〈 0.05）, obviously higher in the ethynylestradiol 4-week group than in the ovariectomized 4-week group （P 〈 0.05）, obviously lower in the ovariectomlzed 12-week group, ethynylestradiol 12-week group and edthynylestradiol on/off group than in the sham-operated 12-week group （P 〈 0.05）, obviously higher in the ovariectomized 12-week group than in the ovarieetomlzed 12-week group （P 〈 0.05）, and obviously lower in the edthynylestradlol on/off group than in the ethynylestradiol 12-week group （P 〈 0.05）. ②All the dynamic metric indexes were obviously higher in the ovariectomized 4 and 12-week groups than in the shamoperated 4 and 12-week groups （P 〈 0.05）, markedly lower in the ethynylestradiol 4 and 12-week groups than in the ovariectomized 4 and 12-week groups （P 〈 0.05）, those in the ethynylestradiol 4 and 12-week groups were close to those in the sham-operated 4 and 12-week groups, obviously higher in the edthynylestradiol on/off group than in the shamoperated 12-week group and ethynylestradiol 12-week group （P 〈 0.05）, those in the edthynylestradiol on/off group were close to those in the ovariectomized 12-week group. ③ The mineral appositional rate, number of osteoclasts and osteoclast circumstance percentage were obviously lower in the sham-operated 12-week group than in the sham-operated 4- Week group （P 〈 0.05）. ④The fluorescent circumstance percentage and bone formation rates were obviously lower in the ovariectomized 12-week group than in the ovariectomized 4-week group （P 〈 0.05）. ⑤The fluorescent circumstance percentage, mineral appositional rate, bone formation rates and osteoclast circumstance percentage were markedly lower in the ethynylestradiol 12-week group than in the ethynylestradiol 4-week group （P 〈 0.05）. CONCLUSION： ①Treatment of 17α-ethynylestradiol for 4 and 12 weeks can both inhibit bone resorption, and then prevent the bone loss of ovariectomized rats, and increase the trabecular area percentage; Meanwhile, it has the side effect of inhibiting bone formation. ②After the withdrawal of ethynylestradiol, the curative effect cannot maintain, the trabecular area percentage will decrease, bone loss will occur again.