Abstract
The number of patients with allergies to pollen and food is increasing worldwide. In Japan, the prevalence of cedar pollinosis, a type I allergy, is nearly 30% and accounts of hay fever are rising. A potential natural remedy for these allergic diseases may be Hita Tenryo Water™ (referred to simply as Hita Tenryo water), water that is pumped from deep underground in the Hita region of Oita, Japan, which has been the subject of various research reports. Here, we investigated the potential of using Hita Tenryo water to suppress the onset of cedar pollinosis in a mouse model and explored the immunological mechanism of the suppression. Test model mice were given Hita Tenryo water ad libitum to drink and received intraperitoneal administration of (i) tap water (Hw1), (ii) 25% Hita Tenryo water (Hw2) or (iii) 100% Hita Tenryo (Hw3). There were no significant differences in body weight change, feed intake, or water intake among the groups during the experimental period. We examined nose rubbing and sneezing as allergic symptoms. The frequency of rubbing and sneezing tended to decrease in the Hw1 and Hw2 group, and significantly decreased in the Hw3 group compared to control. Total IgE levels in serum were also significantly reduced in Hita Tenryo water intraperitoneal administration groups. In vitro examination of the rate of release of β-hexosaminidase from BL-2H3 cells showed that there were no significantly differences between Hita Tenryo water-treated and control cells. In addition, measurement of Th2-related cytokine levels in concanavalin A-stimulated peripheral blood mononuclear cells revealed a significant decrease in IL-4, IL-6, and IL-10 levels in medium (p < 0.01). In contrast, production of IFN-γ significantly increased (p < 0.01). These results indicate that Hita Tenryo water may alleviate and/or suppress allergic symptoms.