Distribution effect of SOST on alveolar bone micro-bone formation in rats induced by Eldecalcitol.

OBJECTIVES

This study controlled experimental and histological study based on an ovariectomized (OVX) rat model, and aimed to clarify the distribution changes of TRAP-positive osteoclasts and sclerostin-positive osteocytes in the alveolar septal area of rats after Eldecalcitol (ELD) treatment, and to explore their association with bone metabolism-related factors, thereby preliminarily elucidating the early pathological mechanism of alveolar osteoporosis.

METHODS

A total of 32 female Wistar rats (8 weeks) were randomly divided into three groups: sham-operated control (Sham, n = 10), ovariectomized (OVX, n = 11), and ovariectomized treated with Eldecalcitol (OVX + ELD, n = 11). Observations were Made at different timepoints, including 1 week and 2 weeks after surgery. OVX rat models were established by bilateral ovariectomy. Eldecalcitol (0.03 µg/kg/day) was administered orally for 2 weeks starting immediately after surgery. Mandibular samples were fixed, decalcified, and prepared into thin sections for histological analyses. Osteocyte distribution and characteristics were studied in detail using TRAP staining, ALP/TRAP staining, and sclerostin/TRAP/silver triple staining techniques. In addition, double staining of RANKL and TRAP was performed to further explore the expression of bone resorption-related molecules.

RESULTS

The experimental results showed that in the bone groove interval area, rats that underwent ovariectomy (OVX) had a small number of TRAP-positive osteoclasts in the early stage (1 week), but this number gradually increased over time. In the OVX group after 1 week of combined treatment with Eldecalcitol, the number of TRAP-positive osteoclasts was significantly reduced. In addition, the expression of sclerostin-positive osteocytes decreased over time, but this decrease was smaller in the combination treatment group.

CONCLUSIONS

This study reveals the distribution of TRAP-positive osteoclasts and sclerostin-positive osteocytes in the alveolar septal area and their correlation with bone metabolism-related factors. Eldecalcitol treatment effectively inhibits osteoclast activity, reduces bone resorption, and significantly mitigates the reduction of sclerostin expression in osteocytes induced by ovariectomy. These findings suggest that Eldecalcitol may regulate alveolar bone metabolism partially by modulating sclerostin expression, making it a promising therapeutic strategy for osteoporosis.