Abstract:

Objective The present study is to evaluate the effects of curcumin on the learning and memory of senescence-accelerated mouse prone 8 (SAMP8) and possible mechanisms by analyzing the p-calcium/calmodulin-dependent kinase II (p-CaMKII) expression in the hippocampus. Methods Experiments were performed using 6-month-old male SAMP8 and senescence-accelerated-resistant strain mice (SAMR1). SAMP8 mice were intragastrically administered curcumin at a dose of 20 or 50 mg/kg body weight or fed the same amount of corn oil (SAMP8 treated with vehicle), once a day for 25 consecutive days. Six mice in each group were performed behavior testing by Morris water maze at day 26 (D26) after treatment. The left side of hippocampus from other 6 mice in each group was homogenized and p-CaMKII expressions in hippocampal membrane fraction were measured by Western blotting. The right side of hippocampus was post-fixed and the distribution and expression of p-CaMKII were observed and analyzed in the hippocampal CA3 region by the immunohistochemistry and optical intensity. Results Treatment of curcumin ［20 and 50 mg/(kg •d) i. g.］ significantly reduced the escape latencies of SAMP8 treated with vehicle (P ＜0.05, P＜0.01) in Morris water maze task. SAMP8 treated with 50 mg/kg of curcumin had a much more time swimming in the target quadrant ( P ＜0.05). In addition, 50 mg/kg of curcumin obviously increased the intensity of p-CaMKII in the stratum lucidum of hippocampal CA3, and relative protein level for p-CaMKII/ GADPH in the hippocampal membrane fraction as well. Conclusion The curcumin treatment may attenuate cognitive deficits of SAMP8 mice in a dose-dependent effect by improving the expression of p-CaMKII in the hippocampus. Thus treatment with curcumin may have a potential therapeutic effect for aging-related cognitive dysfunctions.

Key words: Curcumin , Learning and memory , Calcium/calmodulin-dependent kinase II , Immunohistochemistry , Senescence-accelerated mouse