Biological toxicity of acid electrolyzed functional water: Effect of oral administration on mouse digestive tract and changes in body weight

Objective: Acid electrolyzed functional water has been used in a variety of ways because of its antiseptic action. In the present study, we investigated both the systemic and gastrointestinal effects of ingesting acid electrolyzed functional water, from the perspective of its use in mouthwash. Materials and methods: Seventeen mice (three weeks old) were used in the experiment. Three of the mice (three-week-old group) were euthanized before having been given solid food, whilst the remaining 14 were divided into two groups, one given free access to acid electrolyzed functional water as drinking water (test group) and the other given free access to tap water as drinking water (control group). Changes in body weight, visual inspections of the oral cavity, histopathological tests, and measurements of surface enamel roughness and observations of enamel morphology were recorded after eight weeks. Results: The results showed no significant difference in changes in body weight between the test and control groups. No abnormal findings or measurements were observed for the test group in terms of visual inspections of the oral cavity, histopathological tests, or measurements of surface enamel roughness. In terms of enamel morphology, attrition was seen in the test group. Conclusions: These findings suggest that the use of acid electrolyzed functional water has no systemic effect and is safe for use in mouthwash.

Distinct signaling pathways leading to the induction of human β-defensin 2 by stimulating an electrolyticaly-generated acid functional water and double strand RNA in oral epithelial cells

Abstract Defensins, a major family of cationic antimicrobial peptides, play important roles in innate immunity. In the present study, we investigated whether double-stranded RNA (dsRNA), a by-product of RNA virus replication, can induce human β-defensins-2 (hBD-2) expression in oral epithelial cells (OECs). We also examined the hBD-2-inducible activity of acid-electrolyzed functional water (FW). The results indicated that both dsRNA- and FW-induced hBD-2 expression in OECs. The induction efficiency was much higher for FW than for dsRNA. FW-induced production of hBD-2 was clearly observed by immunofluorescence staining. A luciferase assay was performed with 1.2 kb of the 5′-untranslated region (5′-UTR) of the hBD-2 gene. The results indicated that the nuclear factor-kappa B (NF-κB)-binding site proximal to the translation initiation site was indispensable for dsRNA-stimulated hBD-2 expression, but not in the case of FW. Moreover, FW-stimulated hBD-2 expression did not depend on NF-κB activity; instead, FW inhibited NF-κB activity. Pretreatment of the cells with specific inhibitors against NF-κB further confirmed NF-κB-independent hBD-2 induction by FW. In analogy to the results for intestinal epithelial cells (IECs), the dsRNA signal, but not FW, was sensed by toll-like receptor 3 (TLR3) in OECs. These results suggested that hBD-2 expression induced by dsRNA and FW is regulated by distinct mechanisms in OECs.