Lycopene attenuates insulin signaling deficits, oxidative stress, neuroinflammation, and cognitive impairment in fructose-drinking insulin resistant rats

- Fructose-drinking cause insulin resistance and insulin signaling deficits in rat brain.
- Lycopene attenuates the insulin resistance and insulin signaling deficits.
- Lycopene strengthens antioxidant defense system in fructose-drinking insulin resistant rats brain.
- Lycopene inhibits neuroinflammation in fructose-drinking insulin resistant rats.
- Lycopene improves cognitive function in fructose-drinking insulin resistant rats.

Fructose intake is linked with the increasing prevalence of insulin resistance, and insulin resistance links Alzheimer's disease with impaired insulin signaling, oxidative damage, neuroinflammation, and cognitive impairment. As a member of the carotenoid family of phytochemicals, lycopene is used as a potent free scavenger, and has been demonstrated to be effective in anti-oxidative stress and anti-inflammatory reaction in the models of AD and other neurodegenerative diseases. Here, we investigated the effect of lycopene on learning and memory impairment and the possible underlying molecular events in fructose-drinking insulin resistant rats. We found that long-term fructose-drinking causes insulin resistance, impaired insulin signaling, oxidative stress, neuroinflammation, down-regulated activity of cholinergic system, and cognitive impairment, which could be significantly ameliorated by oral lycopene administration. The results from this study provide experimental evidence for using lycopene in the treatment of brain damage caused by fructose-drinking insulin resistance.