Effects of 20-hydroxyecdysone on improving memory deficits in streptozotocin-induced type 1 diabetes mellitus in rat

We investigate the effects of 20-hydroxyecdysone (20E) on improving memory deficits in the current study by using an animal model of type 1 diabetes mellitus in rats. Animals in control group went on a normal diet. Rats that developed diabetes were divided into 4 groups, including STZ-induced diabetic group which was treated with saline and three 20E groups received different 20E concentrations for 12 weeks. Spatial memory performance was measured in rats by the Morris water maze. The level of nuclear factor-кB (NF-кB) in the brain was determined by real-time quantitative PCR. The mRNA levels and enzyme activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) and glutathione reductase (GR) were analyzed by real-time quantitative PCR and spectrophotometry. The concentrations of brain-derived neurotrophic factor (BDNF) in the brain were detected by ELISA. Compared with the control group, rats in the STZ-induced diabetic group that developed type 1 diabetes exhibited significant memory loss. In addition to the hippocampus CA1 area that displayed severe damage, significantly higher expression levels of NF-кB were observed in these rats. Furthermore, the expression levels of SOD, catalase, GSH-Px GR and BDNF were significantly decreased in rats with diabetes. By contrast, the treatment with 20E, especially at higher concentrations, reversed the above-mentioned conditions caused by diabetes. The results suggest that the 20E has a protective role in counteracting memory deficits in rats with diabetes of rat, possibly through enhancing the antioxidative ability in the brain.