Effects of citric acid administration on femoral trabecular structures in ovariectomized mice

Abstract

To examine the effects of citric acid administration on trabecular structures. Ovariectomized female ICR mice (n = 39), 8 weeks of age, were divided into four groups: ovariectomized control (OVX-control, n = 9, standard diet); citric acid (CIT, n = 10, citric acid 5 g/100 g diet); vitamin K2 (menaquinone 7; VK2, n = 10, vitamin K2 50 µg/100 g diet); and citric acid + vitamin K2 (CIT + VK2, n = 10, citric acid 5 g/100 g diet and vitamin K2 50 µg/100 g diet). After 12 weeks, the bone mass of the right femur was measured using peripheral quantitative computed tomography and the three-dimensional (3-D) trabecular structure of the right femur was assessed using microfocus computed tomography. The bone mineral density was significantly increased in the VK2 group versus the OVX-control group (P < 0.05). In the 3-D trabecular structure analysis, skeletal perimeter and number were significantly greater in the CIT, VK2, and CIT + VK2 groups than in the OVX-control group. Skeletal separation, spacing, and trabecular bone pattern factor were significantly lower in the CIT, VK2, and CIT + VK2 groups than in the OVX-control group. Almost all parameters in node–strut analysis were significantly greater in the CIT, VK2, and CIT + VK2 groups than in the OVX-control group. These results suggest that citric acid improved trabecular structures. However, simultaneous administration of citric acid and vitamin K2 did not have any additional effect.