Abstract: ObjectiveTo investigate the effect of silibinin on learning memory and expression of oxidative stress factor in senescence-accelerated mouse prone 8 (SAMP8).MethodsForty male SAMP8 mice of 13 weeks old were assigned into a model group (gavaged with normal saline),low- and high-dose groups (with 100 and 200 mg/kg silibinin),and positive control group (with 2.6 mg/kg memantine) and 10 senescence accelerated mouse resistant 1 (SAMR1) mice (with normal saline gavage) were included in a normal control group.All the mice were treated once a day for 6 weeks consecutively.We adopted novel object recognition,Y maze and Morris water maze test to evaluate the ability of learning and memory of the mice.Enzyme-linked immunosorbent assay was used to detect oxidative stress-related indicators.ResultsCompared with the control group,the model group showed significantly lower preference index (0.45±0.07),spontaneous alternation rate (0.58%±0.06%) and prolonged escape latency (50.62±11.24 s)(P<0.01 for all);the model group also showed significantly decreased glutathione (GSH,21.13±6.17 mg/mL) and superoxide dismutase (SOD,15.21±0.09 μg/mL) and increased malondialdehyde (MDA,4.02±0.12 nmol/mL) in hippocampus tissue (P<0.05 for all).Compared with the model group,the high-dose silibinin group had significantly higher preference index (0.68±0.09),spontaneous alternation rate (0.70%±0.09%) and shortened escape latency (23.45±11.94 s) (P<0.01 for all);in addition,significantly increased GSH (42.37±12.08 mg/mL),SOD (32.24±0.24 μg/mL) and decreased MDA (2.54±0.21 nmol/mL) in hippocampus tissues were observed in the mice with high-dose silibinin treatment (P<0.05 for all).ConclusionSilibinin could improve learning and memory deficit in SAMP8 mice and the effects may be associated with the increased anti-oxidative stress capability of the mice.