Discussion
In this study, the effect of glabridin and glycyrrhizic acid on chemical composition and mechanical
properties of osteoporoti- cally-changed bones in estrogen-deficient rats is presented for the first
time.
In order to induce estrogen deficiency in mature female rats, the
bilateral cessation of ovaries (ovariectomy) was conducted. This procedure is the direct cause of
estrogen deficiency in the animal body. After 4 weeks of the ovariectomy, there are changes in the
bones which indicate the occurrence of osteoporosis [14,16,19,20]. Similar alterations of bone
remodeling are observed in postmeno- pausal women [1,2,21].
In presented study, after 4 weeks from ovariectomy, the unfavorable changes in chemical composition
and mechanical properties of bones were observed. In the tibia, the femur and the L-4 vertebra, the
increase of the water was connected with the loss of mineral substances.
What is more, bone mechanical strength of estrogen-deficient
rats has been weakened, especially in the tibial metaphysis and femoral diaphysis. The bones showed
increased susceptibility to fractures and were also more sensitive to deformations. Reduction of
the maximal load in the femoral neck was also observed. This worsening of the mechanical properties
of bones in ovariecto- mized rats may be a result of the altered chemical composition as well as
the decrease of the weight of all analyzed bones.
Administration of estradiol at a dose of 0.2 mg/kg po to ovariectomized rats for 4 weeks resulted
in beneficial changes in both the chemical composition and mechanical properties of analyzed bones.
The protective effect observed in this study
oovveerlapsrlaps wwithith tthehe ppreviousrevious sstudiestudies [[1166]]..