Expression of Toll-like receptor 2, Dectin-1, and Osteopontin in murine model of pulpitis

• Published in: Clinical oral investigations 2023-03, Vol.27 (3), p.1177-1192
• Main Authors: Hasan, Arshad, Roome, Talat, Wahid, Mohsin, Ansari, Shazia Akbar, Khan, Javeria Ali, Jilani, Syeda Neha Ahmed, Jawed, Abira, Kiyani, Amber
• Format: Article
• Language: English
• Subjects: Animal models; Animals; Antigens; Dental pulp; Dental Pulp - metabolism; Dentistry; Disease Models, Animal; Immunohistochemistry; Inflammation; Innate immunity; Medical research; Medicine; Mice; Osteopontin; Polymerase chain reaction; Pulpitis - microbiology; TLR2 protein; TLR4 protein; Toll-Like Receptor 2 - metabolism; Toll-Like Receptor 4 - metabolism; Toll-like receptors; Tumor Necrosis Factor-alpha - metabolism; Tumor necrosis factor-TNF; Tumor necrosis factor-α; Zymosan
• ISSN: 1436-3771; 1432-6981; 1436-3771
• DOI: 10.1007/s00784-022-04732-2

Objectives This in vivo animal study aimed to develop a murine model of pulpitis induced by pulp exposure with or without application of zymosan in Naval Medical Research Institute (NMRI) mice and observe expressions of Toll-like receptor (TLR)-2, TLR-4, Dectin-1, Osteopontin (OPN), tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and IL-1ß. Material and methods A total of 168 NMRI mice were divided into two groups, i.e., group A ( n  = 84) (pulpitis induced by pulp exposure only) and group B ( n  = 84) (pulpitis induced by pulp exposure and zymosan application). Right maxillary molar pulps were exposed with ¼ round bur, and animals were sacrificed at 0, 6, 9, 12, 24, 48, and 72 h. The exposed teeth were obtained for real-time polymerase chain reaction (qRT-PCR) analysis and histological and immunohistochemistry (IHC) analysis. Results Histological evaluation revealed a time-dependent steady increase in inflammation. Similar time-dependent increase in the expression of inflammatory cytokines was noted. Group A exhibited an increase in TLR-4, Dectin-1, and OPN at 6 h, while TLR-2 was expressed at 24 h. Group B expressed TLR-2, Dectin-1, and OPN at 9, 48, and 72 h, respectively ( p  ≤ 0.05). Expression of OPN and TNF-α exhibited a similar pattern in both groups. IHC also detected expression of TLR-2, Dectin-1, TLR4, and CD68 in some cells at 6 and 9 h. Conclusions NMRI mice provided for a stable pulp inflammation model. Zymosan may be used to develop pulp inflammation model and study inflammatory response towards fungal antigens. Dental pulp expressed Dectin-1 receptor. OPN and TNF-α exhibited a similar expression pattern. Clinical relevance Innate immunity of dental pulp is capable of detecting fungal pathogens.