Objective: To study the protective and therapeutic effects of Rhodosin and Melatonin on Alzheimer's disease(AD) rats. Methods: D-galactose was intraperitoneally injected in rats for 6 weeks and β-Amyloid 1-40(Aβ 1-40) was injected into bilateral hippocampus to make AD models. Rhodosin and Melatonin were intraperitoneally injected in rats for 4 weeks to determine the protective and therapeutic effects on rats with AD. Y-maze test, and passive avoidance task were used to determine the ability of learning and memory. The content of lipofuscin in the central cortex, the viscous coefficient of mitochondrial membrane, the activity of superoxide dismutase and the content of malondialdehyde in both sides of hippocampus were determined. And the apoptosis of hippocampus neurons was determined with transmission electron microscopy(TEM). Results: Melatonin as an antioxidant significantly improved learning and memory deficits in the rats with AD and reduced the increase in SOD, MDA, the viscous coefficient and lipofuscin to their normal levels, and it also showed the protective effects of apoptosis. Rhodosin showed the similar effects. Conclusion: Rhodosin and Melatonin had preventive and therapeutic effects on rats with AD probably by affecting the free radical levels in rats.
