Haoyang Tian,1,* Hui Chen,2,* Xiaochun Yin,2 Meiyi Lv,3 Lingling Wei,1 Yuna Zhang,4 Shuhan Jia,5 Jingyuan Li,1 Hui Song1 

1School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Jinan, People’s Republic of China; 2Department of Endodontics, Jinan Stomatological Hospital, Jinan, People’s Republic of China; 3Department of Pediatric Dentistry, Jinan Stomatological Hospital, Jinan, People’s Republic of China; 4Department of Stomatology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People’s Republic of China; 5Department of Stomatology, Yancheng NO. 1 People’s Hospital, Yancheng, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Hui Song; Jingyuan Li, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, No. 44-1 Wenhua Road West, Jinan, Shandong, 250012, People’s Republic of China, Tel +86-531-88382912, Fax +86-531-88382923, Email songhui@sdu.edu.cn; jingyuan_31@163.com

Introduction: Diabetes has been recognized as an independent risk factor for periodontitis. Increasing evidences indicate that hyperglycemia aggravates inflammatory response of human periodontal ligament cells (hPDLCs). Carbon monoxide-releasing molecule-3 (CORM-3) is a water-soluble compound that can release carbon monoxide (CO) in a controllable manner. CORM-3 has been shown the anti-inflammatory effect in different cell lineages.
Methods: We stimulated periodontal ligament cells with LPS and high glucose. The expression of inflammatory cytokine was detected by ELISA. RT-qPCR, Western blot and immunofluorescence were used to detect the expression of TLR2, TLR4, RAGE and the activation of NF-κB pathway. We performed silencing and overexpression treatment of RAGE targeting the role of RAGE. We performed the immunostaining of paraffin sections of the periodontitis model in diabetes rats.
Results: The results showed that CORM-3 significantly inhibited the expression of inflammatory cytokine in hPDLCs stimulated with LPS and high glucose. CORM-3 also inhibited LPS and high glucose-induced expression of RAGE/NF-κB pathway and TLR2/TLR4/NF-κB pathway. Silence of RAGE resulted in significantly decreased expression of proteins above. Overexpression of RAGE significantly enhanced the expression of these factors. CORM-3 abrogated the effect of RAGE partially. In animal model, CORM-3 suppressed the inflammatory response of periodontal tissues in experimental periodontitis of diabetic rats.
Discussion: Our research proved CORM-3 reduced the inflammatory response via RAGE/NF-κB pathway and TLR2/TLR4/NF-κB pathway in the process of high glucose exacerbated periodontitis. These findings demonstrated the role of RAGE in the process of high glucose exacerbated periodontitis and suggested that CORM3 be a potential therapeutic strategy for the treatment of diabetes patients with periodontitis.

Keywords: carbon monoxide-releasing molecules, periodontitis, diabetes, receptor for advanced glycation end products, lipopolysaccharide