Efftec Of Long-Term Exposure To Green Tea For Taste System And Taste Preference Behavior In Mice

Obesity and the related diseases are growing a global threat to human health. The fundamental cause of obesity and overweight is the imbalance between dietary intake and energy expenditure. Consequently, the efficient strategies against obesity and overweight are increasing energy expenditure and reducing energy intake. Green tea, as a kind of natural herbal nutrients, arouses a wide attention because of its weight control efficacy. According to recent year’s researches, we know clearly how green tea increase the energy comsumption, but the mechanism about reducing energy intake is rarely. As we all know, gustatory system is the decisive factor for food intake, so we hypothesized that the long-time exposure to green tea maybe alter the characters of peripheral taste organ, taste bud, and then affect the food preference and intake and finallyreach the effect of weight control and lose weight. Adult ICR mice are used and treated with the solution of green tea and its crucial active components during21days, including caffeine, tea polyphenols and L-theanine. Following forementioned chronic exposure, we used the methods of whole-mount preparation of tongue and soft palate epitheliums, immunohistochemistry, laser confocal scanning microscope and Western Blot, discussed the changes of the gustatory peripheral perception system and analyze the functions on taste perception of different active components in green tea. And link to the classic animal behavior TBP (two bottle preference) experiment, analyzed the changes of sweet and fat taste preference, the outcomes are:(1) Chronic administration of green tea and its different active components alters anatomic characters of taste budsChronic administration of green tea and its different active components affect anatomic characters of fungi form taste buds, The number of fungiform taste buds decrease significantly from green tea, caffeine+0.06%tea polyphenols treaed mice, about17.5%.and14.3%All the components can decrease the biggest cross-sectional areas of fungiform taste buds, from1000μm2(control) to900μm2(different exposures). The taste buds cells change differently in fungiform and soft palate. The mice treated with0.5%tea polyphenols, L-theanine,0.06%tea polyphenols+caffeine, decreased about22.8%,14.5%,22.5%,16%in the number of fungiform taste buds and16%,19.2%,10.7%in soft palate taste buds. Little impact was found on fungiform taste buds afetr consumption of green tea and caffeine but opposite on soft palate.(2) Chronic administration of green tea and its different active components alter taste transduction and sensitivity related protein expressionThe outcome of immunohistochemistry showed that green tea and different active components change the expression of taste transduction protein in taste cells with regional different. All the components can significantly decrease the number of a-gustducin-immunopositive cells per fungiform taste bud, about12.3%,20.9%,17.6%,15.3%,16.7%,20.9%(order according to the picture) but have no effects on the circumvallate papillae and soft palate taste buds (except for the caffeine reduce the protein expression in circumvallate papillae). Different exposures have different effects on PLCβ2expression in different parts, mice treated with green tea and caffeine+0.06%tea polyphenol are influenced most, decreased about18.3%,14.2%and15.1%. The number of PLCP2immunopositive cells decreased about19.6%,21.2%,15.3%,21%,9.3%and23%in soft palate.There are no change in circumvallate papillae except green tea and0.5%tea polyphenols. WB detect that the expression of a-gustducin protein in epithelium decrease about50%and70%after green tea and caffeine treated, but PLC(32change little.Compared with control mice, the protein abundance of CB1receptor and leptin receptor changes differently. The quantitative changes of leptin receptor takes on an increasing trend (increased about30%), but decrease the protein abundance of CB1receptor about20%.(3) Variation of sweet and fat taste preference after chronic administration of green tea.The outcome of TBP show that long time exposure of green tea can decrease the preference of sucrose, average reduce20%, increase the sucrose preference threshold notably, from0.32to3.8mmol/L. Increase the preference of AK in high concentration. Decrease the preference of soybean oil, average decrease about25%.In short, chronic administration of green tea and its crucial active components changes the anatomical characters of taste buds and decreases the expression of taste signal transduction and lipocyte control protein, decrease the taste preference of sucrose and soybean oil, which maybe affect the nerve conduction pathway and taste perception, then response for, at least in part, the weight loss. Provide the new theory evidence and research design for natural herbal such as green tea in weight control.