Improvement of Ca balance by Fructus Ligustri Lucidi extract in aged female rats

Abstract

This study aimed to demonstrate and delineate the mechanism of action of Fructus Ligustri Lucidi (FLL) involved in improving Ca balance in aged female rats. FLL could enhance the apparent Ca absorption rate and reduce Ca excretion, via its actions on modulating the levels of calciotropic hormones and CaBPs expression. Fructus Ligustri Lucidi (FLL) is a herb classically used for the treatment of age-related symptoms in China. The present study aimed to determine if FLL could improve calcium balance in aged female rats and delineate its mechanism of action in vivo. Aged Sprague-Dawley rats (11 months of age) were orally administered with ethanol extract of FLL or its vehicle and fed with diets containing different levels of Ca (low Ca diet, LCD, 0.1% Ca; medium Ca diet, MCD, 0.6% Ca; high Ca diet, HCD, 1.2% Ca) for 12 weeks. Serum, urine and feces were collected for biochemical markers and Ca balance determination. mRNA expressions of calcium binding proteins (CaBPs) were determined by real time RT-PCR. The effects of diets and herb were analyzed by both one-way and two-way ANOVA. FLL significantly reduced fecal Ca excretion and induced apparent Ca absorption rate in rats fed with MCD and HCD. FLL increased serum 1,25(OH)(2)D(3) level and duodenal CaBP-9k mRNA expressions in all rats. Renal CaBP-28k mRNA expressions were induced in rats fed with MCD and HCD upon FLL treatment. Our study demonstrated that FLL improved Ca balance in aged female rats by increasing serum 1,25 (OH)(2)D(3) level and vitamin D-dependent CaBPs expression.