Soy isoflavones alleviate periodontal destruction in ovariectomized rats

Abstract

Objective The purpose of this study was to investigate whether soy isoflavone supplementation is effective in preventing periodontal destruction exacerbated by estrogen deficiency (ED) and its potential mechanism. Background The progression of periodontitis is affected by host factors, such as smoking, diabetes mellitus, and steroid use. Bone loss in periodontitis can be aggravated by ED. Methods A rat model of experimental periodontitis (EP) with ED was established by silk ligature and inoculation with Porphyromonas gingivalis, and some EP rats were subjected to bilateral ovariectomy (OVX). The treatment groups received an intravenous injection of 17‐β‐estradiol (E2B) or soy isoflavones (SI) by gavage. The rats were euthanized, and the maxillary jaws, gingiva, and serum were harvested. Tight junction protein and interleukin (IL)‐17 expression, reactive oxygen species (ROS) level, and periodontal destruction were assessed. In addition, we determined whether grainyhead‐like 2 (GRHL2) is required for enhancing the epithelial barrier by SI in an in vitro P. gingivalis infection model. Results Estrogen deficiency impaired the expression of genes encoding tight junction proteins in the gingiva, increased IL‐17 level, and accelerated alveolar bone resorption. SI treatment alleviated tight junction protein expression, decreased IL‐17 and ROS levels, and prevented the absorption of alveolar bone. Furthermore, GRHL2 expression was significantly induced by SI in human oral keratinocytes‐1 (HOK‐1) cells; GRHL2 knockdown impaired the expression of OCLN and ZO‐1 induced by SI treatment. Conclusion Soy isoflavones alleviates periodontitis in OVX rats, as observed by the increased expression of tight junction proteins, and reduced IL‐17 level and alveolar bone loss. The in vitro studies suggested that the enhancement of oral epithelial barrier by SI treatment was partially dependent on GRHL2.

Overview on postmenopausal osteoporosis and periodontitis: The therapeutic potential of phytoestrogens against alveolar bone loss

“…Table 1 summarizes the effect of phytoestrogens against alveolar bone loss. In a recently published study, oral administration of soy isoflavones was found to alleviate experimental periodontitis in estrogen-deficient rats as revealed by the increased expression of tight junction proteins in the gingiva, reduced proinflammatory cytokines, IL-17 and ROS levels (Liu et al, 2022). Attenuation of alveolar bone loss was observed through micro-CT and histologic observation.…”

“…An in vitro P. gingivalis infection model was also used to determine whether grainyhead-like 2 (GRHL2), the epithelial transcription factor and ER-binding partner (He et al, 2020) is required by soy isoflavones to enhance the oral epithelial barrier. It was found that the enhancement of oral gingival epithelial barrier function by soy isoflavones treatment was partially dependent on GRHL2 (Liu et al, 2022).…”

Novel In Situ-Cross-Linked Electrospun Gelatin/Hydroxyapatite Nonwoven Scaffolds Prove Suitable for Periodontal Tissue Engineering

“…The periodontium can be severely destroyed by many oral diseases, including inflammatory processes such as gingivitis and periodontitis, and this lack of knowledge makes it difficult to adequately address these tissue defects from a therapeutic point of view. Since millions of people worldwide are affected by these debilitating diseases, their effective treatment is both a medical and an economic challenge [14][15][16][17][18].…”