The Effect Of Taurine On Capabilities Of Learning And Memory In Alzheimer’s Disease-like RATS

Objective:To investigate the effect of taurine on capabilities of learning and memory in Alzheimer s disease-like rats.Methods:Male SD rats were randomized into 7 groups:control group, sham group, AD model group, positive drug group, low dose, middle dose and high dose of taurine group. Aβ1-40 was injected into the rats hippocampus to make AD model.The positive drug group was given Huperzine A by intragastric administration in the dose of 0.16mg-kg-1·d-1. The three taurine groups were given taurine 200 mg·kg-1·d-1,400 mg·kg-1·d-1 and 600 mg·kg-1·d-1 respectively by intragastric administration for consecutive 4 weeks. Morris maze test was used to determine the learning and memory ability. The activities of acetylcholine(Ach)、acetylcholine esterase (AChE)、choline acetyltransterase (ChAT)、superoxide dismutase (SOD)、the content of malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) were measured in the hippocampus and cortex 24h after Morris maze test. Cerebrum sections were used for HE staining.Results:In Morris maze test, the latencies of the middle dosage and the large dosage of taurine were shorter than those of the model group significantly[(39.08±5.23) (39.11±2.24) (43.21±3.46)s, P<0.05]; Swimming time in the third quadrant and times of traversing platform of the middle dosage and the large dosage of taurine were longer than those of the model group significantly[(38.90±3.35) (38.92±3.31) (34.96±4.30) s,P<0.05],[(4.38±1.06)(4.10±1.10)(2.89±1.69)P<0.05]. Compared to the model group, the content of Ach and the activity of ChAT in hippocampus of the middle dosage and the large dosage of taurine increased significantly[(159.06±13.16) (160.10±9.88) (144.50±17.39)μg/ml,P<0.05], [(225.36±22.30) (222.12±21.41) (201.67±33.80) IU/g, P<0.05],while the activity of Ache was reduced [(122.25±11.99) (120.45±11.20) (143.11±19.68) U/mgprot, P<0.05]. the content of Ach and the activity of ChAT in cortex of the middle dosage and the large dosage of taurine increased significantly, [(160.31±12.64) (159.10±9.83) (143.39±18.70)μg/ml, P<0.05], [(214.81±20.17) (216.06±27.13) (190.89±23.44) IU/g, P<0.05], while the activity of Ache was reduced [(118.88±12.43) (117.05±8.96) (139.37±11.81) U/mgprot, P<0.05]; The activity of SOD and GSH-PX in hippocampus of the middle dosage and the large dosage of taurine strengthened significantly[(209.38±34.48) (209.33±29.67) (179.78±28.38) U·mg-1, P<0.05], [(35.71±7.66) (35.36±6.63) (28.77±8.12) U·g-1, P<0.05],while the content of MDA decreased[(1.93±0.32) (1.89±0.30) (2.38±0.52) nmol·mg-1, P<0.05]。the activity of SOD and GSH-PX in cortex of the middle dosage and the large dosage of taurine strengthened significantly, [(199.38±31.22) (201.05±26.93) (172.00±16.46) U-mg-1, P<0.05], [(32.55±4.44) (33.12±4.12) (27.22±6.48) U·g-1, P<0.05], while the content of MDA decreased[(2.06±0.32) (2.05±0.30) (2.56±0.60) nmol-mg-1, P<0.05]。HE staining showed that taurine could repair the pathological damnification of hippocampus.Conclusion:Taurine has significant protective effect against the decrease of learning and memory of the Alzheimer s disease-like rat at the doses from 400 to 600 mg·kg-1·d-and the mechanism is may be associated with the elevation of antioxidase activity、the improvment of cholinergic nervous system and the repairation of hippocampus.