Systemic and local effects of long-term exposure to alkaline drinking water in rats

Abstract

Alkaline conditions in the oral cavity may be caused by a variety of stimuli, including tobacco products, antacids, alkaline drinking water or bicarbonate toothpaste. The effects of alkaline pH on oral mucosa have not been systematically studied. To assess the systemic (organ) and local (oral mucosal) effects of alkalinity, drinking water supplemented with Ca(OH) 2 or NaOH, with pH 11.2 or 12 was administered to rats (n 36) for 52 weeks. Tissues were subjected to histopathological examination; oral mucosal biopsy samples were also subjected to immunohistochemical (IHC) analyses for pankeratin, CK19, CK5, CK4, PCNA, ICAM-1, CD44, CD68, S-100, HSP 60, HSP70, and HSP90. At completion of the study, animals in the study groups had lower body weights (up to 29% less) than controls despite equal food and water intake, suggesting a systemic response to the alkaline treatment. The lowest body weight was found in rats exposed to water with the highest pH value and starting the experiment when young (6 weeks). No histological changes attributable to alkaline exposure occurred in the oral mucosa or other tissues studied. Alkaline exposure did not affect cell proliferation in the oral epithelium, as shown by the equal expression of PCNA in groups. The up-regulation of HSP70 protein expression in the oral mucosa of rats exposed to alkaline water, especially Ca(OH) 2 treated rats, may indicate a protective response. Intercellular adhesion molecule-1 (ICAM-1) positivity was lost in 6/12 rats treated with Ca(OH) 2 with pH 11.2, and loss of CD44 expression was seen in 3/6 rats in both study groups exposed to alkaline water with pH 12. The results suggest that the oral mucosa in rats is resistant to the effects of highly alkaline drinking water. However, high alkalinity may have some unknown systemic effects leading to growth retardation, the cause of which remains to be determined.

The bactericidal and biofilm removal effect of super reducing water on <i>Streptococcus mutans</i> in three types of orthodontic brackets

“…From a clinical perspective, SRW can be safely applied to the oral cavity. Merne et al [29] showed that the oral mucosae of rats allowed to drink alkaline water (pH, 11.2 and 12.0) for 52 weeks remained unaffected by the high alkalinity without any specific morphologic alterations. However, the application of calcium hydroxide paste, which has a pH almost similar to that of alkaline electrolyzed water, to the oral mucosa of rats and hamsters resulted in cell atypia [30,31].…”

Quantitative Assessment of the Chemical Safety of Groundwater Wells in Two Selected Districts of Rwanda

“…Low water pH will cause redness and irritation to eyes below a pH of 4. And while a water pH of 2.5 or lower is uncommon, exposure to water of this acidity will cause extensive and irreversible damage to the skin cells that detect sensation [14].…”

“…Symptoms of effect of drinking water with high Zinc includes: nausea, vomiting, dizziness, fevers, diarrhea and acute toxicity leading to stomach aches. Other related health effects also include mucous membrane infection [14,15,17].…”

Guidance for the Description of Animal Research in Scientific Publications

“…Specific information about drinking water source, delivery methods, and treatments (e.g., acidification, chlorination, sterilization) is important to provide; some treatments, in particular, are known to affect certain experimental parameters (Bjornsson et al 2003;Hall et al 1980;Hermann et al 1982;Merne et al 2001). In certain types of studies water delivery methods have been known to be an important component of husbandry as well (Gordon and Wyatt 2011).…”