Microcomputed tomographic evaluation of vertebral microarchitecture in pinealectomized scoliosis chickens

Pinealectomy was used to induce scoliosis in Broiler chickens, and the bone microarchitecture of the concave and convex sides in pinealectomized scoliosis chickens was assessed by microcomputed tomography (micro-CT). Few studies have assessed the vertebrae bone microarchitecture of the concave and convex sides in scoliosis although the curvature of the coronal plane is the main deformity in scoliosis. The purpose of this study was to determine whether there are differences in the bone microarchitecture of the concave and convex sides in pinealectomized scoliosis chickens by the technique of micro-CT. The etiology and the pathogenesis of the idiopathic scoliosis remain unclear. Limited information is available on the microarchitecture of vertebrae bone of the concave and convex sides of scoliosis, especially in the earlier stage in scoliosis development. One hundred female Broiler chickens were divided into three groups as follows: the control group (n=20), the sham operation group (n=20), and the pinealectomy group (n=60). Then the pinealectomy group was divided into three groups according to the time of killing the chickens: 1-week after the operation (group P-1 w, n=20), 2 weeks after the operation (group P-2 w, n=20), and 3 weeks after the operation (group P-3 w, n=20), respectively. Posteroanterior radiographs of the spine were taken to detect spinal curvature. Using micro-CT, the bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation of the concave and convex sides of the apex vertebrae in the scoliotic chickens were determined. Independent t-tests were used to assess differences of bone parameter of the concave and convex sides in each pinealectomized group. The incidences of scoliosis in the pinealectomized Broiler chickens were 84.2% (group P-1 w), 88.9% (group P-2 w), and 89.5% (group P-3 w), respectively. In groups P-1 w and P-2 w, there were no differences between the concave and convex trabecular bone microarchitectures. In group 3 w, the BV/TV, Tb.Th, and Tb.N of the concave side were significantly greater than those of the convex side. In the earlier stage of pinealectomized scoliosis chickens, there are no histological evidence of a metabolic abnormality. The greater BV/TV, Tb.Th, and Tb.N of the concave side in group P-3 w may be consistent with Wolff's law and are the secondary response to the scoliotic deformity.