JOURNAL ARTICLE

Effect of naringenin on brain insulin signaling and cognitive functions in ICV-STZ induced dementia model of rats

Wenqing Yang, Jing Ma, Zheng Liu, Yongliang Lu, Bin Hu, Huarong Yu
Neurological Sciences 2014, 35 (5): 741-51
24337945
Recent evidence indicates that severe abnormalities in brain glucose/energy metabolism and insulin signaling have been documented to take a pivotal role in early sporadic Alzheimer's disease pathology. It has been reported that naringenin (NAR), derived from citrus aurantium, exhibits antioxidant potential and protects the brain against neurodegeneration. The current study was designed to further investigate the protective effect of the NAR on neurodegeneration in a rat model of AD induced by an intracerebroventricular (ICV) injection of streptozotocin (STZ), and to determine whether this neuroprotective effect was associated with brain insulin signaling. Rats were injected bilaterally with ICV-STZ (3 mg/kg), while sham rats received the same volume of vehicle and then supplemented with NAR (25, 50 mg, 100 mg/kg, respectively) for 3 weeks. The ICV-STZ injected rats did not have elevated blood glucose levels. 21 days following ICV-STZ injection, rats treated with NAR had better learning and memory performance in the Morris water maze test compared with rats treated with saline. We demonstrated that NAR increased the mRNA expression of INS and INSR in cerebral cortex and hippocampus. In addition, NAR reversed ICV-STZ induced Tau hyper-phosphorylation in both hippocampus and cerebral cortex through downregulation of glycogen synthase kinase-3β (GSK-3β) activity, a key kinase in the insulin signaling. Brain levels of Abeta, which were elevated in ICV-STZ rats, were significantly reduced in NAR-treated rats via upregulation of insulin degrading enzyme. These effects were mediated by increased insulin and insulin receptors expression in the brain, suggesting that insulin sensitizer agents might have therapeutic efficacy in early AD.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
24337945
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"