Baicalin inhibits toll-like receptor 2/4 expression and downstream signaling in rat experimental periodontitis.
Periodontitis is a severe inflammatory response, leading to characteristic periodontal soft tissue destruction and alveolar bone resorption. Baicalin possesses potent anti-inflammatory activity; however, it is still unclear whether baicalin regulates toll-like receptor (TLR) 2/4 expression and downstream signaling during the process of periodontitis. In this study, the cervical area of the maxillary second molars of rats was ligated and inoculated with Porphyromonas gingivalis (P. gingivalis) for 4weeks to induce periodontitis. Some rats with periodontitis were treated intragastrically with baicalin (50, 100 or 200mg/kg/day) or vehicle for 4weeks. Compared with the sham group, the levels of TLR2, TLR4 and MyD88 expression and the p38 MAPK and NF-κB activation were up-regulated in the experimental periodontitis group (EPG), accompanied by marked alveolar bone loss and severe inflammation. Treatment with 100 or 200mg/kg/day baicalin dramatically reduced the alveolar bone loss, the levels of HMGB1, TNF-α, IL-1β, and MPO expression, and the numbers of inflammatory infiltrates in the gingival tissues. Importantly, treatment with 100 or 200mg/kg/day baicalin mitigated the periodontitis-up-regulated TLR2, TLR4 and MyD88 expression, and the p38 MAPK and NF-κB activation. Hence, the blockage of the TLR2 and TLR4/MyD88/p38 MAPK/NF-κB signaling by baicalin may contribute to its anti-inflammatory effects in rat model of periodontitis. In conclusion, these novel findings indicate that baicalin inhibits the TLR2 and TLR4 expression and the downstream signaling and mitigates inflammatory responses and the alveolar bone loss in rat experimental periodontitis. Therefore, baicalin may be a potential therapeutic agent for treatment of periodontitis.
Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Resarech, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China; Department of Periodontology, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China.
Jun-Yi
JY
Sun
Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center; Xi'an City, Shaanxi Province, China.
Dong-Ling
DL
Li
The Second Affiliated Hospital of Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China.
Yan
Y
Dong
Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Resarech, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China; Department of Periodontology, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China.
Chun-Hui
CH
Zhu
Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Resarech, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China; Department of Periodontology, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China.
Jin
J
Liu
Department of Periodontology, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China.
Jue-Dan
JD
Li
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China.
Tao
T
Zhou
Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Resarech, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China; Department of Periodontology, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China.
Jian-Zhong
JZ
Gou
Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Resarech, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China; Department of Periodontology, College of Stomatology, Xi'an Jiaotong University; Xi'an City, Shaanxi Province, China. Electronic address: drliang@mail.xjtu.edu.cn.
Ang
A
Li
Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center; Xi'an City, Shaanxi Province, China. Electronic address: zwj@mail.xjtu.edu.cn.
Wei-Jin
WJ
Zang
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D016866:Bacteroidaceae Infections / Q000188:drug therapy* / Q000276:immunology; D005419:Flavonoids / Q000627:therapeutic use*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008297:Male; D023421:Models, Animal; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism*; D010518:Periodontitis / Q000188:drug therapy* / Q000276:immunology; D016966:Porphyromonas gingivalis / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D031364:Scutellaria baicalensis / Q000276:immunology*; D015398:Signal Transduction / Q000187:drug effects; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*
D000893:Anti-Inflammatory Agents; D005419:Flavonoids; C507781:Myd88 protein, rat; D053594:Myeloid Differentiation Factor 88; C495343:Tlr2 protein, rat; C495347:Tlr4 protein, rat; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; C038044:baicalin
Baicalin; MyD88; NF-kappaB; Periodontitis; Porphyromonas gingivalis; Toll-like receptor