关键词: 学习, 记忆, 半乳糖, 衰老, 阿尔茨海默病

Abstract: Objective To investigate the effects of β-amyloid on learning memory and hippocampus neuron ultrastructures in aging rats induced by D-galactose (D-gal). Methods Using the water labyrinth test, the rats with quickly reaction were selected and randomly divided into four groups（n=12）:control group，Aβ group，D-gal group， and D-gal+Aβ group. In the D-gal group and D-gal+Aβ group, each animal was injected intraperitoneally with the D-gal 50 mg•kg^-1•d^-1 for 6 weeks, the decrepitude animal model was established. In the control group and Aβ group, each animal was injected intraperitoneally with same quantity of physiology saline. At the 7th week, the rats in Aβ group and D-gal+Aβ group were injected with Aβ_25-35 into bilateral hippocampal regions, 1 μL in each side; and the rats in control group and D-gal group were injected with same quantity of physiology saline. After the model was established successfully, Morris water maza test was used to determine the ability of learning and memory. Ultrastructures of the hippocampus neurons were observed under electron microscope. Results ①One week after operation, the escape latencies were longer in Aβ group, D-gal group, and Aβ+D-gal group than that in control group (P<0.05),obviously in Aβ+D-gal group (P<0.01). ②The hippocampus neuron ultrastructures in control group were nearly normal, mitochondria cristae of the hippocampus neurons in Aβ group broke. The hippocampus neurons in D-gal group had lipofuscin deposit. In D-gal+Aβ group, nucleuses pyknosis was fonud and chondriosomes swelled. The crista broke and became emptey bubble. Conclusion The combination of D-gal and Aβ can induce a conspicuous reduction of learning-memory ability in rats, and increase the aging degree of brain.

Key words: learning, memory, galactose , aging, Alzheimer disease