目的研究补肾中药女贞子对去卵巢大鼠钙代谢及维生素D依赖型基因表达的影响。方法大鼠去卵巢手术处理4周后,给药治疗14周。血清、尿液及粪便中钙水平采用比色法测定。RT-PCR技术分析小肠及肾脏基因表达。结果大鼠去卵巢后体内钙流失显著增加,表现在血钙下降,尿钙及粪钙排泄增加。女贞子可以有效防止尿钙及粪钙排泄增加,并恢复血钙水平。RT-PCR分析表明雌二醇和女贞子都可以抑制去卵巢引起的小肠维生素D受体(VDR)mRNA表达下降。女贞子对肾脏25-羟基维生素D 1-羟化酶(1-OH ase)及25-羟基维生素D 24-羟化酶(24-OH ase)mRNA无明显作用,但却可以提高肾脏钙结合蛋白-9k(C aBP-9k)及钙结合蛋白-28 k(CaBP-28k)的基因表达。结论女贞子能够改善雌激素缺乏所引起的钙失衡状态,主要是通过提高小肠对活性维生素D的敏感性及加强肾脏对钙的重吸收而发挥作用的。

Objective To investigate the effect of Fructus Ligustri Lucidi(FLL),a kidney-tonifying Chinese herbal medicine,on calcium metabolism and vitamin D-dependent gene expression in ovariectomized(OVX)rats. Methods Four weeks after OVX surgical operation the OVX rats were ig administered with estradiol and FLL for 14 weeks. Ca²⁺Level in serum,urine,and feces was measured by colorimetric methods,and gene expressions in duodenum and kidney were analyzed by reversed transcriptase polymerase chain reaction(RT-PCR). Results Ovariectomy of rat 1ed to significant loss of calcium in vivo,as demonstrated by decreasing serum Ca²⁺1evel and increasing Ca²⁺excretion rate in urine and feces in OVX rat group. Treatment of OVX rats with FLL could effectively restore serum Ca²⁺level and prevent the increase of Ca²⁺excretion from urine and feces. RT-PCR Analysis showed that both estradiol and FLL could prevent 0VX-induced decrease of mRNA expression in duodenal vitamin D receptor(VDR). In kidney,FLL did not alter mRNA expressions of 25-hydroxyvitamin D 1-hydroxylase(1-OHase)and 25 -hv-droxyvitamin D 24-hydroxylase(24-OHase),while increased the mRNA expression Ievels of renal calciumbinding protein-9k(CaBP-9k)and calcium-binding protein-28k(CaBP-28k). Conclusion FLL could improve the state of calcium imbalance induced by estrogen deficiency and the potential mechanism that contributes to the improvement of calcium status by FLL nfight involve the increase in intesfinal sensitivity to active vitanfin D through its up-regulation of VDR expression in duodenum and the enhancement in Ca²⁺reabsorption via the up regulation of calcium binding proteins expression in kidney.

香港特别行政区科技研究发展计划(AOE/P-10/01)项目资助课题(B-Q7673-ZF89)