Influence of chronic high-salt diet intake on experimental periodontitis: a preclinical study in rodents

This study explored how chronic consumption of a high-salt diet (HSD) would affect periodontal tissues and periodontitis (PD) progression and remission using a PD ligation model. Male Wistar rats received a control diet (CD) or HSD for 16 weeks. Animals with each diet were allocated into healthy, PD (by ligation), and PD-remission (PD-R) groups. After 10 days, animals were sacrificed, except the PD-R groups, which had ligature removal and were sacrificed after another 10 days. PD severity and alveolar bone loss were evaluated clinically, morphometrically, and histologically in the right maxilla. The gene expression analysis assessed the molecular pathways behind the diet and PD effects in the left maxilla. Clinical assessment of the gingival bleeding index (GBI), probing pocket depth (PPD), and tooth mobility (TM) revealed that HSD exacerbated PD and reduced its recovery. Bone metabolic markers were elevated in HSD groups, particularly CTX and TRAP. Micro-CT assessment showed increased alveolar crest heights (ACH) and impaired alveolar bone microstructure in PD groups, while HSD worsened these impairments. Likewise, the gingival histological alterations by PD were aggravated in HSD animals. In the alveolar bone, expressions of bglap, ctsk, and hif1a were downregulated by HSD. Meanwhile, in the gingival tissues, expressions of eln, il6, mmp9, and tnf genes were increased by HSD without PD, while expressions of eln, il6, mmp9, tnf, and vegf genes were decreased in the PD-R groups. Chronic HSD intake was associated with altered periodontal structure, aggravated ligature-induced PD, and impaired early periodontal remission after ligature removal.