Precocious hippocampal structural and functional changes in gestational protein-restricted male elderly offspring: an Alzheimer-simile disease model?

Background: Maternal undernutrition has been associated with psychiatric and neurological disorders characterized by learning and memory impairment. Considering the lack of evidence for this, we aimed to analyze the effects of gestational protein restriction on learning and memory function later in life. This research associates behavioral findings with hippocampal cell numbers and protein content related to neurodegenerative brain disease. Methods: Experiments were conducted in animals subjected to a low-protein (LP, 6% casein) or regular-protein (NP, 17% casein) diet throughout their pregnancy. Behavioral tests, isolated hippocampal isotropic fractionator cell studies, immunoblotting, and survival lifetime tests were performed. The results confirmed that the birthweight of LP male pups significantly reduced relative to NP male pups and that hippocampal mass increased in 88-week-old LP compared to age-matched NP offspring. We used the Morris water maze proximity measure, which is the sum of 10 distances each second between rat position and location of a hidden platform target, as a suitable test for assessing age-related learning or memory impairment in aged offspring. Results: The results showed an increased proximity measure in 87-week-old LP rats (52.6 x 104 {+/-} 10.3 x 104 mm) as compared to NP rats (47.0 x 104 {+/-} 10.6 x 103 mm, p = 0.0007). In addition, LP rats exhibited anxiety-like behaviors compared to NP rats at 48 and 86 weeks of life. Additionally, the estimated neuron number was unaltered in LP rats; however, glial and other cell numbers increased in LP compared to NP rats. Here, we showed unprecedented hippocampal deposition of brain-derived neurotrophic factor, {beta}-amyloid peptide (A{beta}), and tau protein in 88-week-old LP compared to age-matched NP offspring. To date, no predicted studies showed changes in hippocampal neuron and glial cell numbers in maternal protein-restricted elderly offspring. The current data suggest that maternal protein restriction has a high impact on lifespan and brain structure, and function. Conclusion: the gestational protein restriction may accelerate hippocampal function loss, impacting learning/memory performance, and supposedly developing diseases similar to Alzheimer's disease (AD) in elderly offspring. Thus, we propose that maternal protein restriction could be a probable, elegant, and novel method for constructing an AD-like model in adult male offspring.