Objective:To explore the protective effects of interleukin-10 (IL-10) pretreatment on the behavioral and molecular biochemical changes of Alzheimer’disease(AD) rat models and its possible mechanism. Methods:Okadaic acid(OA) was microinjected into the hippocampus of rats to establish the AD rat models. The escape latency of rats was tested by water maze. Western-blot method was used to detect the expression of protein phosphatase 2A (PP2A) and amyloid precursor protein (APP) in the hippocampus. Simultaneously,the ratio of CD4+ cells to the CD8+ cells in the mesenteric lymph node cells was examined by flowcytometry. Results:The latent period in water maze of rats that were injected with OA in the hippocampus was significantly increased,and the latent period of the rats with high concentration of OA injection was longer than that of the rats with low concentration of OA injection. The PP2A protein expression in hippocampus after the OA injection was down-regulated,and the inhibitory effect of OA on PP2A protein expression was enhanced as the OA concentrations increased. Conversely,APP protein expression in hippocampus was increased with the elevated concentrations of OA injected in the hippocampus. After IL-10 and OA were injected into the rat hippocampus respectively,the latent period of water maze was significantly lower than that of the AD rats only with the OA injection. IL-10 reversed the inhibitory effect of OA on PP2A expression and alleviated the augument of APP;furthermore,IL-10 reversed the increasing of CD4+/CD8+ induced by OA and caused the CD4+/CD8+ return to the control level. Conclusion:AD-like changes can be induced by the microinjection of OA into the hippocampus. IL-10 can reverse the AD-like changes induced by OA,and the effects of IL-10 are dose-dependent and also closely related to its inhibition of inflammatory reaction.