Figure 3.

Decreased collecting lymphatic vessels and lymph flow in periodontal tissues of RA-associated periodontitis. Six-month-old TNF-Tg RA mice and their WT littermates were used. (A) Paraffin sections of maxillae were subjected to IF for PDPN (red) and αSMA (green). Representative images of periodontal tissue showing the distribution of PDPN⁺/αSMA⁻ lymphatic capillaries (red), PDPN⁺/αSMA⁺ collecting LVs (yellow, indicated by blue arrows), and PDPN⁻/αSMA⁺ blood vessels (green). (B) Quantification of the PDPN⁺αSMA⁻ area, PDPN⁺αSMA⁺ area or PDPN⁻αSMA⁺ area to tissue area (%) was determined. (C) An example of in vivo washout of ICG: 1 μl (0.5 μg/μl) of ICG was injected sub-epithelially in the buccal oral mucosa to the maxillary first molar area. The total fluorescence in the entire posterior facial area was measured using an optical imager (IVIS Spectrum) at 60 min post-injection. The measurement was repeated every 90 min for a 7-h period. ICG clearance (%) was quantified. Values shown are mean ± SEM. (D) Gene expression levels were measured by RT-qPCR. Values were calculated as CT (gene of interest)/2 – CT (Gapdh) × 100. *p < 0.05 versus WT at the same time point. Between six and eight mice per group were included in each experiment. Two-tailed unpaired Student’s t-tests were performed.