Abstract:

Methods Forty male SD rats were randomly divided into control group， diabetic periodontitis model group（model group）， low dose （100 mg·kg^－1） of GSPE group and high dose （200 mg·kg^－1） of GSPE group； there were 10 rats in each group. Except for control group， the rats in other groups were used to establish the diabetic periodontitis models by periodontal ligation combined with intraperitoneal injection of streptozotocin （STZ）. After the successful establishment of the models， the rats in low and high doses of GSPE groups were given 100 and 200 mg·kg^－1 GSPE， respectively， while the rats in control group and model group were given the same amount of normal saline once a day for 8 weeks. The general situation of the rats and the changes of blood glucose levels were observed， the pathomorphology of periodontal tissue of the rats in various groups were observed by HE staining， the alveolar bone absorption of the rats in various groups was measured， the activities of superoxide dismutase （SOD） and the catalase （CAT） and the levels of reactive oxygen species （ROS） and malondialdehyde （MDA） in periodontal tissue of the rats in various groups were detected by related kits.Enzyme-linked immunosorbent assay（ELISA） method was used to detect the levels of tumor necrosis factor-α （TNF-α）， interleukin-1β（IL-1β） and interleukin-6（IL-6） in serum of the rats in various groups. The expression levels of Toll-like receptor 4（TLR4） and nuclear factor-κB（NF-κB） proteins in periodontal tissue of the rats in various groups were detected by Western blotting method. Results Compared with control group， the rats in model group showed obvious symptoms of “three more and one less”；the level of blood glucose of the rats was increased obviously（P<0.05）， the inflammatory cells were infiltrated in periodontal connective tissue， periodontal tissue was damaged， and the alveolar bone absorption amount was increased（P<0.05）；the activities of SOD and CAT in periodontal tissue were significantly decreased （P<0.05）， the levels of ROS and MDA were significantly increased （P<0.05）， the levels of TNF-α， IL-1β and IL-6 in serum were significantly increased（P<0.05），and the expression levels of TLR4 and NF-κB proteins were significantly increased （P<0.05）. Compared with model group， the general condition of the rats in low and high doses of GSPE groups was obviously improved，the levels of blood glucose were reduced（P<0.05）， periodontal tissue damage was obviously reduced，the alveolar bone absorption amounts were reduced（P<0.05）， the activities of SOD and CAT in periodontal tissue were significantly increased （P<0.05）， the levels of ROS and MDA were significantly decreased （P<0.05）， the levels of TNF-α， IL-1β and IL-6 in serum were significantly decreased（P<0.05），and the expression levels of TLR4 and NF-κB proteins were significantly decreased （P<0.05）. Compared with low dose of GSPE group， the activities of SOD and CAT in periodontal tissue of the rats in high dose of GSPE group were significantly increased （P<0.05）， the levels of ROS and MDA were significantly decreased （P<0.05）， the levels of TNF-α， IL-1β and IL-6 in serum were significantly decreased（P<0.05），and the expression levels of TLR4 and NF-κB proteins were significantly decreased （P<0.05）. Conclusion GSPE can improve the periodontal inflammation in the diabetic periodontitis rats， and its mechanism may be related to regulating the TLR4 and NF-κB signaling pathway in periodontal tissue. Objective To explore the improvement effects of grape seed proanthocyanidin extract （GSPE） on the periodontal inflammation in the diabetic periodontitis rats， and to clarify its mechanism.

Key words: Grape seed proanthocyanidin extract, Diabetes mellitus, Periodontitis, Toll-like receptor 4, Nuclear factor-κB