孕激素对去势雌性大鼠骨密度及骨形态计量作用的初步研究

目的　了解孕激素对去势雌性大鼠骨密度及骨形态计量作用。方法　 5 0只 6月龄Wistar雌性大鼠随机分为 5组 :假手术组和卵巢切除组、卵巢切除后分别加安宫黄体酮 2mg组、安宫黄体酮 2 0mg组和倍美力组。手术后 7d喂药 ,用药后 3个月处死。测定各组大鼠子宫湿重、全身及股骨骨密度并取大鼠椎骨、胫骨组织切片进行形态计量分析。结果　两组孕激素组子宫湿重与卵巢切除组相同 ,均显著低于假手术组与倍美力组 (P <0 0 0 1)。假手术、雌、孕激素组全身骨密度测定均大于卵巢切除组 (P <0 0 5 )。各组股骨骨密度无显著差异。组织切片观察显示 ,假手术与倍美力组骨小梁粗壮、饱满、结构完整 ;卵巢切除组则纤细、断裂、完整性差。孕激素组骨小梁结构优于卵巢切除组但不及假手术及倍美力组。计量分析显示孕激素组椎骨骨小梁面积明显大于卵巢切除组(P <0 0 5 ) ,但低于倍美力组 (P <0 0 5 )。胫骨骨小梁面积与卵巢切除组相仿 ,均明显低于假手术和倍美力组 (P <0 0 5 )。孕激素 2mg与 2 0mg组间无明显差异。结论　两种剂量的安宫黄体酮对卵巢切除大鼠骨质疏松均有一定防治作用 ,但从骨组织形态计量分析 ,其作用较弱 ,与结合雌激素相比 ,尚不足以维持骨量

Effects of progesterone on bone mass density and histomorphometry of ovariectomized rats

Objective\ To study the effects of progesterone on the bone mass density (BMD) and histomorphometry of ovariectomized rats. Methods\ Fifty female Wistar rats,6 months old,were randomized into five groups:ovariectomized grouip (OVX);sham\|OVX;the remaining three groups were ovariectomized and treated with medroxyprogesterone acetate (MPA)2 mg,MPA 20 mg and premarin,respectively.Seven days after operation,all rats were given the medicine for 3 months.Then,they were sacrificed,and their uterine wet weight,total and femoral BMD were measured.Pathomorphology and histomorphometry of the tibia and vertebra of all rats were observed. Results\ The uterine wet weight of both MPA groups were the same as that of OVX group,but they were all significantly lower than those of sham\|OVX and premarin groups ( P<0.001 ).Total BMDs of sham\|OVX,premarin and progesterone groups were all higher than that of OVX group( P<0 05 ).There was no difference in femoral BMD between different groups.Histomorphology showed sturdy and intact trabecular bone in sham\|OVX and premarin groups,while slender,broken and less intact trabecular bone was observed in OVX group.The mean trabecular area (MTA) of vertebra of both MPA groups were significantly higher than that in OVX groups ( P< 0 05),but lower than in premarin groups ( P< 0 05).No difference in MAT of tibia was observed between both MPA groups and OVX group;they were all significantly lower than those in sham\|OVX and premarin groups ( P< 0 05).There was no difference between MPA 2 mg and 20 mg groups. Conclusion\ MPA of both dosages has certain preventive effect on osteoporosis in ovariectomized rats,but it is less strong than conjugated estrogen and is not enough to maintain the bone mass.