Dental and periodontal phenotype in sclerostin knockout mice

Abstract

Sclerostin is a Wnt signalling antagonist that controls bone metabolism. Sclerostin is expressed by osteocytes and cementocytes; however, its role in the formation of dental structures remains unclear. Here, we analysed the mandibles of sclerostin knockout mice to determine the influence of sclerostin on dental structures and dimensions using histomorphometry and micro-computed tomography (μCT) imaging. μCT and histomorphometric analyses were performed on the first lower molar and its surrounding structures in mice lacking a functional sclerostin gene and in wild-type controls. μCT on six animals in each group revealed that the dimension of the basal bone as well as the coronal and apical part of alveolar part increased in the sclerostin knockout mice. No significant differences were observed for the tooth and pulp chamber volume. Descriptive histomorphometric analyses of four wild-type and three sclerostin knockout mice demonstrated an increased width of the cementum and a concomitant moderate decrease in the periodontal space width. Taken together, these results suggest that the lack of sclerostin mainly alters the bone and cementum phenotypes rather than producing abnormalities in tooth structures such as dentin.

Effect of sclerostin removal <i>in vivo</i> on experimental periodontitis in mice

“…However, since the importance of sclerostin came to light, many studies have focused on the effects of upregulation or downregulation of sclerostin expression. This led to development of the SOST-KO mouse model, which was used for comparison with WT mice in terms of changes to dental and periodontal structures (14). Most studies have suggested that sclerostin deficiency mainly alters alveolar bone and cementum phenotypes.…”

“…SOST, the gene for sclerostin, is located at position 11.2 on the long arm of chromosome 17. SOST knockout (KO) in mice may not cause abnormality of tooth structures such as dentin, but may alter the bone and cementum phenotypes (14). Furthermore, inflammation can induce sclerostin expression (15).…”

Transforming growth factor-β1 increases sclerostin in fibroblasts of the periodontal ligament and the gingiva

“…Thus, preclinical studies are required to reveal the response of the periodontium and the role of SOST in vivo. Results from SOST knock out mice underline the relevance of research in this direction [7].…”

“…SOST knock out mice show high bone mass and changes in the periodontium [5] [5] [6] [7]. These changes of the periodontium include increased width of cementum and decreased periodontal space width [7]. Furthermore, SOST knock out mice showed enhanced bone healing [8].…”

“…SOST is produced during tooth development and has been proposed to be involved in dentin formation [4]. SOST knock out mice show high bone mass and changes in the periodontium [5] [5] [6] [7]. These changes of the periodontium include increased width of cementum and decreased periodontal space width [7].…”