Bone mineral density is increased in the cadmium-induced omphalocele chick model by using three-dimensional micro-computed tomography

Abstract

Purpose: The cadmium (Cd) chick model has been described as a reliable model of omphalocele. Skeletal anomalies, including lumber lordosis, can be seen in the Cd chick model, as well as in the human omphalocele. Bone deformations, such as lordosis, are associated with high bone mineral density (BMD). Recently, three-dimensional microcomputed tomography (3DMCT) has been used to investigate skeletal development in small animal embryos. We used 3DMCT to test the hypothesis that the BMD is increased in the Cd-induced omphalocele chick model.

Methods: After a 60-h incubation, chicks were exposed to either chick saline or Cd in ovo. Chick embryos were harvested at embryonic day 16.5 (E16.5) and were divided into control (n = 8) and Cd (n = 9). Chicks were then scanned by 3DMCT. The body volume, bone volume, bone/body volume ratio, bone mineral quantity and BMD were analysed statistically (significance was accepted at p < 0.05).

Results: Bone mineral density (mg/cm³) was significantly increased in the Cd group compared to control group (235.3 ± 11.7 vs 223.4 ± 4.6, p < 0.05), whereas there was no significant difference in the bone/body volume ratio between the Cd group and the control group (0.7 ± 0.1 vs 0.6 ± 0.0). The body volume (cm³) (0.3 ± 0.2 vs 0.3 ± 0.1), bone volume (cm³) (0.2 ± 0.2 vs 0.2 ± 0.1), and bone mineral quantity (mg) (51.3 ± 41.6 vs 41.5 ± 16.5) were not significantly different between the two groups.

Conclusions: Increased BMD may be associated with lordosis of the vertebral column in the Cd-induced omphalocele chick model, stimulating osteogenesis by activating the canonical Wnt signalling pathway.

Keywords: Bone mineral density; Cadmium; Chick embryo; Lordosis; Omphalocele.