Alleviation Effects Of Taurine On The Chronic Stress Of Rats

Nowadays, with the increasingly fierce competition in society, more and more nerve diseases are increasing under the pressure of life and work. Long-term chronic stress can inhibit neural regeneration in the hippocampus, induce the decline of learning and memory ability, and finally cause depression, Alzheimer disease and other neurodegenerative diseases. Taurine has an important role in the maintenance of the structure and function of nervous system. It can improve the cognitive and memory function of the brain in a wide range of animals. The purpose of this study was to investigate the effect and mechanism of taurine on learning and memory of rats with chronic stress, in ordet to provide valuable reference for the prevention and treatment of related mental disorders caused by chronic stress.In this study, the stress animal model was established by 28 days of chronic unpredictable mild stress combined with single cage rearing. Adult male Wistar rats were randomly divided into six groups:Rats in taurine control group (T 1, T 2) were given standard diet, adequate drinking water and were daily intraperitoneal injected of 200 mg/kg and 500 mg/kg taurine respectively; rats in the blank control group (C) were daily intraperitoneal injected with the same volume of saline; rats in the chronic stress model group (M) were kept in solitary cages and were given 28 day of chronic mild unpredictable stress, rats in taurine treatment groups (T Ⅰ+M, TⅡ+M) received the same stress as the model group and were daily intraperitoneal injected with 200 mg/kg and 500 mg/kg taurine. Regular measurement The body weight and sucrose preference rate were mearsured once per week, water maze and open field tests were carried out at the end of the experiment to judge the model establishment and the effects of Taurine on the behavior of rats with chronic stress. Concentrations of 5-ELISA (5-HT), serotonin norepinephrine (NE), Dobaamine (DA), cortisol (CORT), glutamate (Glu), interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-alpha) were detected in serum and hippocampus of rats, total RNA and protein were extracted from the hippocampus of rats in order to detect the mRNA and protein expressions of growth factor (FGF-2), vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF) and related factors in the Notch signaling pathway.The Results showed that the body weight increase slowly in the chronic stress rats and there is a significant difference compared with the normal rats (P<0.05), sucrose preference decreased(P<0.05). The excitability and mobility of chronic stress rats declined in the open field test, and the exploring ability and memory decreased in the Morris water maze (P<0.05). Taurine could significant increase the body weight and sucrose preference of rats with chronic stress (P<0.05), and raise the mobility of rats in the open field test, increase the horizontal and vertical scores. In the morris water maze, Taurine could elevate the space exploring, learning abilities and memory of rats, shorten the exploring lentency of rats (P<0.05). ELISA detection results showed that serum and hippocampal concentrations of Glu, CORT, IL-1(3, TNF-a levels increased significantly (P<0.01),5-HT, NE, DA content decreased significantly (P<0.01) in rats with chronic stress. qPCR and Western Blotting analysis found that mRNA and protein expressions of FGF-2 (P<0.05), VEGF (P<0.01), BDNF (P<0.01) and Notch 1(P<0.01), Hesl (P<0.01), Hes5 (P<0.05), Jaggedl (P<0.01) in the Notch pathway were significantly down regulated in the model group. Whereas, Taurine could significant decrease the serum and hippocampal Glu, CORT, IL-1β, TNF-a, increase the levels of 5-HT, NE, DA(P<0.05). At the same time, Taurine could also unregulated the mRNA and protein expressions of FGF-2, VEGF, BDNF and Notch 1, Hes1, Hes5, Jaggedl in the Notch pathway (P<0.05).These results suggested that 28 days of unpredicatable chronic mild stress combined with single cage rearing can successfully establish the chronic stress modle. Taurine can imnprove the exploring ability, learning ability and ameliorate the anxiety and anxious feeling of rats cause by chronic through regulating the neurotransmitters, hormone levels, inflammatory factors as well as the mRNA and protein expressions of neurodevelopment factors in the hippocampus.