Effects of Stromal Cell‐Derived Factor 1 on Osteoblast Activity During Orthodontic Tooth Movement
Yoshiyuki Hamada, Yuji Ishida, Albert Chun‐Shuo Huang, Kenta Hamahara, Duangtawan Rintanalert, Kai Li, Kasumi Hatano‐Sato, Jun Hosomichi, Risa Usumi‐Fujita, Takashi OnoABSTRACT
Objective
This study aimed to clarify the relationship between stromal cell‑derived factor 1 (SDF‑1) and osteoblast‐related responses in periodontal ligament (PDL) during orthodontic tooth movement (OTM) after tooth extraction, based on the hypothesis that local inhibition of SDF‑1/C‑X‑C chemokine receptor type 4 (CXCR4) signaling with the CXCR4 antagonist AMD3100 would attenuate osteoblast differentiation and alveolar bone remodeling during OTM.
Methods
Thirty‐six 6‐week‐old Wistar/Sprague–Dawley male rats were randomly divided into control and experimental groups. After the extraction of the maxillary left first molar, the maxillary left second molar (M2) was moved mesially with a 10‐gf force following the local injection of phosphate‐buffered saline or AMD3100 into the buccal and palatal gingiva adjacent to the M2 in the control and experimental group, respectively. Micro‐computed tomography was performed to assess tooth movement and alveolar bone changes. Histological and immunohistochemical analyses were performed to evaluate periodontal tissue morphology and the percentages of SDF‐1‐, CXCR4‐, RUNX2‐, and BGLAP‐positive cells on the tension side of the PDL. Quantitative reverse transcription PCR was used to assess expression levels of SDF‐1, CXCR4, RUNX2, and BGLAP.
Results
OTM distance and mesial tilt angle were significantly reduced in the experimental group. RT‐PCR showed that SDF‐1, CXCR4, and RUNX2 expression levels were significantly downregulated from Day 1 through Day 7, whereas BGLAP expression was significantly decreased only on Day 1. Immunohistochemical analysis of the tension side of the PDL demonstrated significantly reduced SDF‐1‐ and CXCR4‐positive cells on Day 3 and RUNX2‐positive cells on Day 7 in the experimental group. In contrast, the BGLAP‐positive cells did not differ significantly at any time point.
Conclusion
Local inhibition of SDF‐1/CXCR4 signaling reduced OTM and altered early alveolar bone remodeling after tooth extraction. The combined gene expression and immunohistochemical findings suggest that the SDF‐1/CXCR4 axis may contribute to osteoblast differentiation, particularly through RUNX2‐related responses during the early phase of OTM.
Trial Registration
Not applicable.