RESUMEN
OBJECTIVES: Previous research demonstrated that diabetes is one of the leading causes of learning and memory deficits. Naringin, a bioflavonoid isolated from grapefruits and oranges, has potent protective effects on streptozotocin (STZ)-induced diabetic rats. Recently, the effects of naringin on learning and memory performances were monitored in many animal models of cognitive impairment. However, to date, no studies have investigated the ameliorative effects of naringin on diabetes-associated cognitive decline (DACD). In this study, we investigated the effects of naringin, using a STZ-injected rat model and explored its potential mechanism. MATERIALS AND METHODS: Diabetic rats were treated with naringin (100 mg/kg/d) for 7 days. The learning and memory function were assessed by Morris water maze test. The oxidative stress indicators [superoxide dismutase (SOD) and malondialdehyde (MDA)] and inflammatory cytokines (TNF-a, IL-1ß, and IL-6) were measured in hippocampus using corresponding commercial kits. The mRNA and protein levels of PPARγ were evaluated by real time (RT)-PCR and Western blot analysis. RESULTS: The results showed that supplementation of naringin improved learning and memory performances compared with the STZ group. Moreover, naringin supplement dramatically increased SOD levels, reduced MDA levels, and alleviated TNF-α, IL-1ß, and IL-6 compared with the STZ group in the hippocampus. The pretreatment with naringin also significantly increased PPARγ expression. CONCLUSION: Our results showed that naringin may be a promising therapeutic agent for improving cognitive decline in DACD.
RESUMEN
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-1ß 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-α, IL-1ß 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.