Fig. 2
From: Osteoclastic effects of mBMMSCs under compressive pressure during orthodontic tooth movement
Mice that received intravenous infusion of mBMMSCs exhibit increased OTM. a OTM model in mouse oral cavity. The mouse maxillary incisor was used as anchor, 30 g force was applied, and the left maxillary first molar was moved mesially with a spiral spring. M1, first molar; M2, second molar; I, Incisor. b Fluorescence microscopy images showed that GFP was expressed in mBMMSCs transfected with GFP-lentivirus before injection. c The experimental schedule of OTM. Two groups of mice received an orthodontic stress device for 10 days. mBMMSCs were infused into the tail vein on days 0 and 5 and then sacrificed 10 days from day 0. d, e After applying orthodontic force for 3 days, immunohistochemistry revealed green fluorescence-positive cells on the tension and compression side periodontal ligament of orthodontic teeth in the saline injection and GFP-labelled mBMMSC groups. The large white arrow represents the direction of orthodontic force, the yellow dotted frame indicates the enlarged area, and the small white arrow represents GFP-positive mBMMSCs. d-i, e-i The tension side of the periodontal ligament, and d-ii, e-ii the compression side of the periodontal ligament, and blue indicates the nucleus, as shown by DAPI staining. Comp, compression surface; Tension, tension surface; PDL, periodontal ligament; NS, injection normal saline group; mBMMSCs, injection stem cell group. N = 5 mice/group. f Statistical results of green fluorescence-labelled mBMMSCs in the periodontal ligament of the compression side and tension side of the first molar in the mBMMSC-injected group. *P < 0.05 versus the tension side. g Occlusal view of the molar area 10 days after OTM. The first molars were moved mesially far away from the second and third molars (N = 5 mice/group). h Micro-CT analysis demonstrated movement of the first molar in the OTM of both groups. I. j Statistical results of OTM of mice in the normal saline and stem cell injection groups. NS, injection normal saline group; mBMMSCs, injection stem cell group. The red dotted line represents the tooth movement distance. *P < 0.05 versus NS group, **P < 0.01 versus NS group. Scale bars in b, d and e are 50 μm, the scale bars in d-i, d-ii, e-i and e-ii are 20 μm, and scale bars in h are 500 μm