Gene expression of Toll-like receptors in acquired immunodeficiency pulp

Objectives: Toll-like receptors (TLRs) mediate signals from bacterial cell wall components in relation to inflammatory reactions. The present study investigated the expression of TLR-2 and TLR-4 in inflamed pulp to elucidate the innate immune mechanism on the acquired immunodeficiency mouse. Methods: Eighteen 7-week-old female Scid mouse and eighteen BALB/c mouse were used in this study. The expression of TLR-2 and TLR-4 in inflamed pulp was investigated by quantitative RT-PCR method and immunohistochemistry. Experimental teeth and total RNA isolated from pulp tissue from 3, 6, 9, 12, 24 and 72 hours after bacterial dentinal infection. TLR-2-, TLR-4- and CD64-positive cells were investigated with immunohistochemistry by ABC methods. Results: The TLR- 2 and TLR-4 mRNA were expressed on 3 hours in both Scid and BALB/c pulp. TLR-2 and TLR-4 mRNA levels in Scid was 1/10 - 1/100 fold lower than the each mRNA level in BALB/c. TLR-2, TLR-4 - positive cells detected on macrophage, odontblast, and dendritic cells in inflamed pulp of each mouse. Conclusions: These results suggested that TLR-2 and TLR-4 may be regulated during the early stage of pulp inflammation, and innate immune system regulated for bacterial infection in acquired immunodeficiency pulp.