Murine OLP leads to local inflammation and oral dysbiosis. (A) OLP using a 5-0 silk suture with 2 knots (∼1 mm apart) located on both sides of the gap between the first and second molars (pointed out with orange dotted ellipse) bilaterally is depicted. (B) Representative tartrate-resistant acid phosphatase (TRAP)–stained sections of gingival tissues harvested at each time point after ligature placement at low (original magnification ×100; scale bar, 100 μm) and high (enlarged yellow frame, original magnification ×400; scale bar, 50 μm) magnifications are shown (1 = the first molar; 2 = the second molar; B = alveolar bone; G = gingival epithelium; arrowheads mark osteoclasts). (C) Total number of osteoclasts per TRAP-stained slide at the ligature site for each time point after ligature insertion. Results represent the mean ± the SD (n = 3 per group, ∗P < .05; ∗∗∗P < .001; and ∗∗∗∗P < .0001 determined using the Mann-Whitney U test). (D) Representative sagittal 3-dimensional and bidimensional (yellow dotted frame) views of the maxillary molars 0 and 14 days after insertion of ligatures are shown. Double-headed yellow arrows mark the distance from the cementoenamel junction to the alveolar bone crest (CEJ-ABC). (E) CEJ-ABC length on the buccal side of the ligature site at each time point after insertion of ligatures is depicted. Bars show the mean ± the SD (n = 6 per group, ∗∗∗P < .001 determined using the Mann-Whitney U test). (F-J) For the isolation of oral bacteria, ligatures were collected from mice 3 hours after ligature placement (day 0) or 14 days after ligature placement (day 14). (F) The relative abundance of microbiota (family level) in the oral cavity and fecal contents at each time point after insertion of ligatures analyzed by 16S rRNA sequencing are shown. (G-H) PCoA by AMOVA of family composition for oral (G) and fecal (H) microbiota from each mouse (n = 4-5 per group). (I) α-Diversity (Shannon index) of oral and fecal microbiota at day 0 and day 14 after OLP is shown (n = 4-5 per group, ∗P < .05 determined using the Mann-Whitney U test). Data are shown as means ± SDs. (J) Volcano plots of differential expression sequencing 2 (DESeq2) analysis showing the amplicon sequence variants identified to the family level features of oral and fecal microbiota that are differentially abundant between the control and OLP groups on day 0 of allo-HCT (n = 4-5 per group). Blue-square (control) and orange-circle (OLP) dots represent bacterial families that significantly differ (log₂-fold change of >1, adjusted P value < .05) between each group. The black dots represent families whose abundance is similar between the 2 groups (P value is not significant or the log₂-fold change is <1). (K) Body weight change of mice after mock or OLP are shown. Data are presented as the mean ± SD (n = 5 per group). Statistical significance was tested using the Mann-Whitney U test. (L) Representative hematoxylin and eosin–stained histology sections of skin, liver, small intestine, and large intestine at days 0 and 14 after OLP are shown. No significant differences were observed between naïve and OLP mice in any of the tissues examined. Scale bar, 100 μm. (M) Pathological scores of the skin, liver, small intestine, and large intestine at day 0 and day 14 after OLP. The pathology score is based on the diagnostic criteria for cGVHD and reflects the extent of inflammation (day 0 vs day 14, n = 5 per group). Panels B through E and K through M are representative data of 2 independent experiments.