Luteolin Is a Potential Immunomodulating Natural Compound against Pulpal Inflammation

Figure 7

Luteolin inhibits alveolar bone loss in a mouse model of experimental endodontic-periodontal complex lesions. (a) Schematic illustration of the experimental endodontic-periodontal complex lesion model in C57BL/6 mice. A 6-0 silk ligature was tied around the maxillary second molar, and microvesicles (MVs) derived from dental pulp (DP-1) cells were simultaneously injected as illustrated. (b) On day 1, the mRNA expression of TNF-α in gingival tissue was analyzed. Mice were injected with 1000 ng of DP-1-derived MVs with (MV Lut) or without (MV Ctrl) luteolin pretreatment. (c) Time course retention of injected MVs in the mouse periodontal tissue was monitored using fluorescent microscopy. MVs (1000 ng) were labeled with PKH26 (red) before administration. Nuclei were stained with DAPI (blue). AB: alveolar bone; T: tooth; P: pulp. (d) Intensity of PKH-26-labeled fluorescent MVs at 24, 48, and 72 h after injection was measured. (e) Three-dimensional microcomputed tomography (micro-CT) images of the maxillae of each treatment group on day 7 after ligature placement. Scale  μm. (f–i) Periodontal bone resorption analysis was performed using a split-mouth experimental design: one side of the maxilla was ligated and locally injected with the indicated amount of MVs or 100 ng of LPS from E. coli and P. g (f, g), whereas the other side without ligation served as the control. (f, h) Relative alveolar bone resorption volume was calculated for each group (nonligated–ligated). (g, i) The ratio of bone volume to tissue volume (BV/TV). Error bars represent the , (b), 6 (d, f–i). ns: not significant, , , , . The statistical significance of differences between groups was determined using one-way ANOVA, followed by correction for multiple comparisons using Tukey’s post hoc test.

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