雄性大鼠内生源性睾酮和雌二醇水平与增龄性骨量丢失的关系研究

目的:研究增龄雄性大鼠内生源性睾酮(T)和雌二醇(E2)水平与骨量丢失的关系。方法:35、70、160、700和800日龄大鼠(每组6只),用骨组织形态计量学方法测量及计算骨小梁面积百分数(%Tb.Ar)、骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)以及骨小梁分离度(Tb.SP);放射免疫分析法测定血清T和E2水平。分析增龄雄性大鼠内生源性T和E2水平变化与骨组织形态计量学变化的关系。结果:①增龄雄性大鼠T和E2水平与骨量密切相关。②大鼠从幼年→成年→老年至衰老,性激素水平的变化和骨量的变化是同步的,T、E2水平增加伴随骨量的增加;T、E2水平降低则伴随骨量的减少,70～160日龄大鼠,T、E2、%Tb.Ar、Tb.N均达到峰值并维持在稳定水平,700日龄大鼠除Tb.Th和Tb.SP外则明显降低。③雄激素的变化与雌激素的变化是同步的,35、70、160、700及800日龄各组的性激素结果依次是:T(ng/d l):118.53±18.35,345.49±54.63,368.83±60.03,61.15±21.12,60.35±19.27;E2(pg/m l):10.35±1.82,16.92±3.13,17.20±2.51,5.87±2.34,5.53±2.48。其骨组织形态计量学结果依次是:Tb.Ar(%):19.52±2.23,26.28±2.18,28.37±1.21,15.62±1.68,14.21±0.89;Tb.Th(μm):35.45±1.63,50.13±3.58,60.23±8.25,75.62±9.72,78.78±11.21;Tb.N(No/mm):5.98±1.21,8.07±0.86,8.30±1.22,2.63±1.35,2.48±1.62;Tb.SP(μm):126.34±18.15,136.26±15.27,261.08±76.43,323.12±78.12,323.12±78.12,330.23±50.20。结论:增龄过程中骨量变化和性激素水平变化密切相关;雄激素和雌激素对骨骼生长和骨量维持均起着重要作用。

Relationship between the levels of sex hormones and loss of bone mass in aging male rats

Objective ： To investigate the relationship between the level of sex hormones and the loss of bone mass in aging male rats. Methods： Thirty male Sprague-Dawley rats were equally divided into five age groups and sacrificed at 35, 70, 160, 700 and 800 postnatal days （PD） , followed by measurement of the % Tb · Ar, Tb · Th, Tb · N and Tb · SP by bone histomorphometry and detection of the levels of serum testosterone （T） and estradiol （E2） by radioimmunoassay. The relationship between the changes Of the T and E2 levels and those of bone histomorphometry was analyzed. Results ： T and E2 levels were closely correlated with the bone mass in the aging male rats. The changes in T and E2 levels were simultaneous with those in the bone mass with the growth of the rats. T, E2, % Th · Ar and Tb · N reached the peak in the 70 and 160 PD groups, and markedly decreased in the 700 PD group except Th · Th and Tb ·SP. The T levels in the 35, 70, 160,700 and 800 PD groups were （ 118.53 ± 18.35 ） ng/dl, （345.49 ±54.63 ）ng/dl, （368.83 ±60.03） ng/dl, （61.15 ±21.12） ng/dl and （60.35 ±19.27） ng/dl, changing simultaneously with the E2 levels, which were （10.35 ±1.82） pg/ml, （16.92 ±3.13） pg/ml, （17.20 ±2.51） pg/ml, （5.87 ±2.54） pg/ml and （5.53 ±2.48） pg/ml, respectively. The metrological parameters of the bone structure in the five groups were as follows, Tb · Ar： （ 19.52 ± 2.23 ） %, （26.28±2.18） %, （28.37±1.21） %, （15.62±1.68） % and （14.21 ±0.89） % ; Tb · Th： （35.45 ± 1.63） μm, （50.13 ±3.58） μm, （60.23 ±8.25） μm, （75.62±9.72） μm and （78.78±11.21） Ixm; Tb. N： （5.98±1.21） n/mm, （8.07 ±0.86） n/mm, （8.30±1.22）n/ram, （2.63±1.35） n/remand （2.48 ±1.62） n/ram; Tb. SP： （126.34±18.15） μm, （136.26± 15.27） μm, （261.08±76.43） μm, （323.12±78.12） μm and （330.23±50.20） μm. Conclusion： Changes in the levels of sex hormones are closely correlated with those of bone mass. Both testosterone and estradiol are essential for bone development and bone mass maintenance.