Experimental Study On The Anti-aging Effects Of Green Tea Polyphenols

ObjectiveThis study was designed to evaluate the effect of Green Tea Polyphenols (GTP) fromtwo aspects: one is to study the effect of GTP on spatial learning and memory ability,immune indexes, and free radicals of D-galactose-induced aging mice model; the otheris to study the effects of GTP on the impairment of learning and memory in miceinduced by scopolamine. This paper is to study anti-aging effects of GTP and itsmechanism. The objective is to provide theoretical foundation and experimental basisfor the further research and development of GTP.MethodThe subacute aging model mice were made by D-galactose，the model mice of acquiredmemory disorder were made by scopolamine. After100,250and625mg/kg of GTPwere treated by intragastric administration different days, learning and memory abilityof mice was measured by step down test and water maze test. The effect ofantioxidation of GTP was also observed on the D-galactose induced subacuteaging-model mice, at the end of the behavior experiment, each mouse was weighted,and then sacrificed, and their brains, spleen, thymus, testicle and epididymis wereharvested, for weighting to compare the organ coefficient alternations during the wholeexperiment. Activity of SOD and content of MDA in serum and brain were determined,brain SOD, MDA, monoamine oxidase-B (MAO-B) and Nitrous Oxide System (NOS)Were determined for each group. The Pathological morphous changes in mice hippocampus were detected with the method of Hematoxylin-eosin staining and themorphological changes of hippocampal neurons were observed under microscope.Results1. Effect on GTP on aging in mice induced by D-galactoseCompared with normal control group, mice in model group exhibited a series ofsignificant aging symptoms, such as behavior impairments, brain, spleen and thymuswere shrinked, SOD activity of blood and brain of aging model mice were significantlylower, the content of MDA of blood and brain of aging model mice increasedsignificantly, MAO activity of brain of aging model mice increased significantly, NOSactivity of brain of aging model mice decreased significantly, which indicated the agingmodel was established successfully in this study. In the tests of the methods ofstep-down, the low, middle and high dose of GTP (100,250,625mg/kg) could decreasethe mistaken reaction times (P <0.05), and prolong the incubation of the first mistakenappearance significantly (P <0.01); In the water maze test, the low, middle and highdose of GTP (100,250,625mg/kg) also could decrease the mistaken reaction times andshorten the incubation period to some extent (P <0.05or P <0.01). Middle and highdose of GTP(250,625mg/kg)could raise the organ coefficient of brain, spleen, thymusand to some extent (P <0.05or P <0.01); the low, middle and high dose of GTP (100,250,625mg/kg) could increase serum and brain SOD activity significantly (P <0.01),reduce serum and brain MDA significantly (P <0.01), decrease the content of MAO-Bin brain significantly (P <0.01), and enhanced NOS activity in brain to some extent (P<0.05or P <0.01). Pathological section showed that the brain tissue of the mice ofnormal control group, Piracetam group and high dose of GTP (625mg/kg) had a clearhippocampus structure with high density, small gap; the hippocampus structure in modelgroup and low dose of GTP (100mg/kg) was not clear, the density of cells the inhippocampus was low, the gap among the cells was large. 2. Effect on GTP on learning and memory disorder in mice induced by scopolamineThe acquired memory disorder model mice were induced by scopolamine. In the stepdown test, compared with normal control group, the error numbers increased (P <0.05)and the latency decreased significantly in the model group (P <0.01). In the water mazetest, compared with normal control group, the error numbers of model group and thelatency were significantly prolonged (P<0.01). In the step down test, the middle andhigh dose of GTP (250,625mg/kg) as well as Piracetam could decrease the number oferrors (P<0.05), prolonged the latency significantly (P <0.01); In the water maze test,the low, middle and high dose of GTP (100,250,625mg/kg) could decrease themistaken reaction times (P <0.05) and shorten the incubation period (P <0.05or P <0.01).ConclusionGTP had obvious anti-aging effects on subacute aging model induced by D-galactose. Itcould improve the spatial learning and memory of aging mice induced by D-galactose,resisted free radicals damage to improve antioxidant capacity, improved the spleen andthymus weight index, enhanced immune function and inhibited necrosis of hippocampuscells. GTP could improve the acquired memory disorder on the model mice induced byscopolamine.