Inhibition of CTSK reduced TLR4-, TLR5-, and TLR9-positive cells in the periodontal gingival lesion area. A through F) IHC stains and quantification of TLR4-positive (A and B), TLR5-positive (C and D), and TLR9-positive (brown) (E and F) cells indifferent groups with or without ODN (3.606 mg · kg−1 · wk−1) treatment at 8 weeks. Red arrows indicate positive cells. Bottom rows are enlarged images of the boxed areas in the lesion area (magnification ×40). G) Normal serum served as a negative control. W/ = with; W/O = without; Inf = infection; N.S. = not significant. * P <0.05, † P <0.01, ‡ P <0.001. n = 5, repeated three times. Scale bars = 25 μm.