Enhanced learning of normal adult rodents by repeated oral administration of soybean transphosphatidylated phosphatidylserine

Luteolin Attenuates Cognitive Dysfunction Induced By Chronic Cerebral Hypoperfusion Through the Modulation of The PI3K/Akt Pathway in Rats

Introduction

In our study, we evaluated the beneficial effect of luteolin in the treatment of cognitive dysfunction in rat models induced by cerebral hypoperfusion by two-vessel occlusion (2-VO).

Material and Methods

Seventy-five male Sprague Dawley rats were subjected to 2-VO surgery, in all but 15 (the sham group, group I) the ligation being permanent to impair cognitive abilities. The sham group rats received saline instead of a drug; 15 2-VO rats were not injected at all (the model group, group II); 15 2-VO rats were administered luteolin at 50 mg/kg b.w. (the lut 50 group, group III); to a further 15 luteolin was given at 100 mg/kg b.w. (the lut 100 group, group IV); and the final 15 received nimodipine at 16 mg/kg b.w. as positive controls (the nimodipine group, group V). Object recognition and Morris water maze tests were performed to investigate memory ability. A Western blot test was also conducted to assess expression of phosphatidylinositol 3-kinase (PI3K), its downstream target protein kinase B (Akt), and the phosphorylated form (P-Akt) in cerebral cortex and hippocampus tissue samples.

Results

Significant variations in the discrimination index in the object recognition test, the escape latencies in the Morris water maze test, and expression levels of PI3K-p110α and PI3K-p85 were observed three months after 2-VO surgery in both lut groups, with a significant change in the nimodipine group compared to the model group. P-Akt and Akt were expressed significantly higher in both lut groups and the nimodipine group than in the model group.

Conclusion

Luteolin treatment of rats cognitively dysfunctional after experimental cerebral hypo perfusion was neuroprotective by activating the PI3K/Akt signals which inhibit neuronal death in the cerebral cortex and hippocampal region.

Glycerophospholipid Supplementation as a Potential Intervention for Supporting Cerebral Structure in Older Adults

Modifying nutritional intake through supplementation may be efficacious for altering the trajectory of cerebral structural decline evident with increasing age. To date, there have been a number of clinical trials in older adults whereby chronic supplementation with B vitamins, omega-3 fatty acids, or resveratrol, has been observed to either slow the rate of decline or repair cerebral tissue. There is also some evidence from animal studies indicating that supplementation with glycerophospholipids (GPL) may benefit cerebral structure, though these effects have not yet been investigated in adult humans. Despite this paucity of research, there are a number of factors predicting poorer cerebral structure in older humans, which GPL supplementation appears to beneficially modify or protect against. These include elevated concentrations of homocysteine, unbalanced activity of reactive oxygen species both increasing the risk of oxidative stress, increased concentrations of pro-inflammatory messengers, as well as poorer cardio- and cerebrovascular function. As such, it is hypothesized that GPL supplementation will support cerebral structure in older adults. These cerebral effects may influence cognitive function. The current review aims to provide a theoretical basis for future clinical trials investigating the effects of GPL supplementation on cerebral structural integrity in older adults.

Krill-Derived Phosphatidylserine Improves TMT-Induced Memory Impairment in the Rat

The present study examined the effects of krill-derived phosphatidylserine (Krill-PS) on the learning and memory function and the neural activity in rats with trimethyltin (TMT)-induced memory deficits. The rats were administered vehicle (medium-chain triglyceride: MCT) or Krill-PS (50, 100 mg/kg, p.o.) daily for 21 days. The cognitive improving efficacy of Krill-PS in TMT-induced amnesic rats was investigated by assessing the Morris water maze test and by performing choline acetyltransferase (ChAT), acetylcholinesterase (AChE) and cAMP responsive element binding protein (CREB) immunohistochemistry. The rats with TMT injection showed impaired learning and memory of the tasks and treatment with Krill-PS produced a significant improvement of the escape latency to find the platform in the Morris water maze at the 2^nd and 4^th day compared to that of the MCT group (p<0.05). In the retention test, the Krill-PS+MCT groups showed increased time spent around the platform compared to that of the MCT group. Consistent with the behavioral data, Krill-PS 50+MCT group significantly alleviated the loss of acetylcholinergic neurons in the hippocampus and medial septum compared to that of the MCT group. Treatment with Krill-PS significantly increased the CREB positive neurons in the hippocampal CA1 area as compared to that of the MCT group. These results suggest that Krill-PS may be useful for improving the cognitive function via regulation of cholinergic marker enzyme activity and neural activity.

n-3 phosphatidylserine attenuated scopolamine-induced amnesia in middle-aged rats

Phosphatidylserine (PS) extracted from bovine brain differs from transphosphatidylated soybean lecithin PS (SB-PS) in its n-3 long-chain polyunsaturated fatty acid (LC-PUFA) content. Both, however, were suggested to affect cognitive performance. We compared the effect of chronic administration of a novel n-3 LC-PUFA PS conjugates (n-3 PS) versus SB-PS, fish oil (FO), SB-PS+FO, or control oil in middle-aged rats, on brain fatty acids composition and performance in behavioral tasks. Our hypothesis was that the n-3 LC-PUFA vehicles will affect these outcomes better than the other diets. Brain phospholipid docosahexaenoic acid levels increased significantly (p=0.0434) with n-3 PS only. None of the treatments affected the animals' task performance in compare with the control, although reversal from the non-match-to-sample to match-to-sample rule in the T-maze differed (p=0.0434) between the experimental diets. Conversely, the acquisition of the Morris water maze task was impaired by scopolamine (SCO) in all but the n-3 PS group (p=0.0019). In the probe, when pretreated with SCO, the SB-PS+FO group and to a lesser degree the n-3 PS group, spent longer latency times (p=0.0390) in the non-peripheral zones of the water maze compared to the control; this may be interpreted as anxiolytic-like behavior. These results suggest that the n-3 LC-PUFA carrier may play a role in these fatty acids bioavailability and their impact on specific cognitive processes.