Puerarin ameliorates cognitive deficits in streptozotocin-induced diabetic rats

Previous research has indicated that Diabetes is a high risk of learning and memory deficits. Puerarin, an isoflavonoid extracted from Kudzu roots, has been reported to possess antioxidant, anti-inflammatory, anti-apoptotic and anti-diabetic properties which are useful in the treatment of various diseases. Recently, Puerarin was found to have the effects on learning and memory performances in humans and animal models. However, up to now, there is no detailed evidence on the effect of Puerarin on diabetes-associated cognitive decline (DACD). In this study, we designed to assess the effects of Puerarin on diabetes-associated cognitive decline (DACD) using a streptozotocin (STZ)-injected rat model and exploring its potential mechanism. Diabetic rats were treated with Puerarin (100 mg/kg per d) for 7 days. The learning and memory function was evaluated by morris water maze test. The acetylcholinesterase (AChE), choline acetylase (ChAT), oxidative indicators [malondialdehyde (MDA) and superoxide dismutase (SOD)] and inflammatory cytokine (TNF-a, IL-1 beta and IL-6) were measured in hippocampus by using corresponding commercial kits. mRNA and Protein levels of Bcl-2 were analyzed by RT-PCR and Westernblot. The results showed that supplementation of Puerarin improved the learning and memory performances compared with the STZ group by the morris water maze test. In addition, Puerarin supplement significantly prevented AChE and MDA activities, increased ChAT and SOD activities, and alleviated the protein level of TNF-alpha, IL-1 beta and IL-6 in the hippocampus compared with the STZ group. Moreover, the pretreatment with Puerarin also significantly increased the Bcl-2 expression. It is concluded that Puerarin possesses neuroprotection to ameliorate cognitive deficits in streptozotocin-induced diabetic rats by anti-inflammatory, antioxidant and antiapototic effects.