Histomorphological study of the spinal growth plates from the convex side and the concave side in adolescent idiopathic scoliosis

Abstract

Asymmetrical growth of the vertebrae has been implicated as one possible etiologic factor in the pathogenesis of adolescent idiopathic scoliosis. The longitudinal vertebral growth derives from the endochondral ossification of the vertebral growth plate. In the present study, the growth plates from the convex and concave side of the vertebrae were characterized by the method of histology and immunohistochemistry to evaluate the growth activity, cell proliferation, and apoptosis. Normal zoned architectures were observed in the convex side of the growth plate and disorganized architectures in the concave side. The histological grades were significantly different between the convex and the concave side of the growth plate in the apex vertebrae (P < 0.05). The histological difference was also found significant statistically between end vertebrae and apex vertebrae in the concave side of vertebral growth plates (P < 0.05). The proliferative potential indexes and apoptosis indexes of chondrocytes in the proliferative and hypertrophic zone in the convex side were significantly higher than that in the concave side in the apex vertebral growth plate (P < 0.05). There was a significant difference of the proliferative potential index (proliferating cell nuclear antigen, PCNA index) between convex side and concave side at the upper end vertebra (P < 0.05). The difference of the proliferative potential index and apoptosis index were found significant statistically in the concave side of the vertebral growth plate between end vertebrae and apex vertebrae (P < 0.05). The same result was also found for the apoptosis index (terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate biotin nick end labeling assay, TUNEL index) in the convex side of vertebral growth plate between end vertebrae and apex vertebrae (P < 0.05). Some correlation were found between radiographic measurements and proliferation and apoptosis indexes. The difference in histological grades and cellular activity between the convex and concave side indicated that the bilateral growth plate of the vertebrae in AIS patients have different growth kinetics which may affect the curve progression.

Epiphyseal Fusion in the Human Growth Plate Does not Involve Classical Apoptosis

“…Most studies relay on TUNEL technique only, which often overestimates the number of apoptotic nuclei, as it labels not only fragmented DNA but also DNA in the process replication and repair. In many studies, TUNEL positive chondrocytes were observed not only in the hypertrophic layer where cells are assumed to die before being incorporated into the newly formed bone, but also in all zones of the growth plate (6,17,18). When re-evaluating pictures of growth plate chondrocytes positive for TUNEL staining, a high diversity of results could be found.…”

“…When re-evaluating pictures of growth plate chondrocytes positive for TUNEL staining, a high diversity of results could be found. Cell morphology is not always complementing TUNEL positivity and when data are presented, cells often do not look like cells in the process of undergoing apoptosis, but as healthy viable cells without showing signs of cell shrinkage and pyknotic nuclei (6,17,18). Thus, the TUNEL method is very sensitive, requires precise temporal control of each step (28) and must be verified by other techniques like EM or molecular markers of apoptosis.…”

“…It is uncertain whether the chick growth plate is comparable with the human, and studies in rodents are limited by the fact that growth plate fusion does not occur during sexual maturation in rats and mice. The only studies done in human tissues are not very extensive involving TUNEL analyses performed in spinal growth plates and slipped capital femoral epiphysis growth plates (6,17,18). To resolve this issue, we decided to jointly collect human growth plate tissue samples obtained during epiphyseal surgery performed in children at different stages of development.…”

Adolescent idiopathic scoliosis: evidence for intrinsic factors driving aetiology and progression

“…Similarly, significantly greater proliferative and apoptotic chondrocytes have been reported in the convex side than in the concave side in the apex vertebral growth plate in AIS [62]. It is known from studies of joint cartilage degeneration that proliferative hypertrophic chondrocytes display a differential phenotype.…”

The use of non‐adult vertebral dimensions as indicators of growth disruption and non‐specific health stress in skeletal populations

“…An increase in vertebral body height is achieved via the process of columnar proliferation, differentiation, and mineralization of chondroblasts on the superior and inferior faces of each of the centra (Stevens and Williams, 1999; Wang et al, 2007). As new bone is laid down on these surfaces the vertebral column increases in length, therefore contributing to an increase in sitting height (Fig.…”