Abstract: Objective: To investigate the protective effect of low-frequency magnetic stimulation on periodontal membrane injury mediated by high sugar. Methods: Human periodontal membrane cells were cultured by resuscitation in vitro, which were randomly divided into normal control group, high sugar model group, and low-frequency magnetic stimulation group (3 subgroups). Flow cytometry method was used to detect the changes in cell cycle. TUNEL method was used to detect apoptosis. Colorimetric method was used to detect Caspase-3, 6, and 9 activities, and reverse transcription PCR and Western-blot were used to detect CXCL1, CXCL2, and its receptor CXCR2 gene and protein expression levels. Results: Compared with the normal control group, the apoptosis of human periodontal membrane cells increased in the high sugar model. Caspase-3, 6, and 9 activities were all improved (P<0.05). The expressions of CXCL1, CXCL2, and its receptor CXCR2 genes and proteins were significantly reduced (P<0.05). Compared with the high-sugar model group, the cell apoptosis rate in the low-frequency magnetic stimulation group decreased, and the Caspase-3, 6, and 9 activities decreased (P<0.05). CXCL1, CXCL2, and its receptor CXCR2 gene and protein expression increased (P<0.05). The effect on the cell cycle was not obvious (P>0.05). When comparing three subgroups, the change in stimulus intensity above 1.5T was the most obvious (P<0.05). Conclusion: High sugar conditions lead to apoptosis of human periodontal membrane cells, and low-frequency magnetic stimulation has protective effect on human periodontal membrane cell injury induced by high sugar.

Key words: low-frequency magnetic stimulation, human periodontal ligament cells, high glucose, injury