Memory Loss Reversal In Mice

Memory Loss Reversal In Mice

Anna Wright, Writer

Have you ever walked into a room only to forget what you were doing or called someone on your phone to ask for help in finding the same device? This memory loss is an unfortunate byproduct of ageing; however, scientists from the University of Cambridge and the University of Leeds have conducted a study proving that it can be reversible in mice and potentially humans as well. 

Perineuronal nets (PNN’s) are structures surrounding certain neurons that control the plasticity₁ of the brain, including the neuroplasticity₂ related to memory. These structures also contain compounds, specifically chondroitin 4-sulphate (C4S) and chondroitin 6-sulphate (C6S), that impact memory and become imbalanced with age. C4S decreases neuroplasticity while C6S increases neuroplasticity. Because the levels of C4S increase as the organism ages, its abilities to learn and remember are negatively affected. Conversely, scientists theorized that if they were able to increase the level of C6S in the PNN’s of older mice, their memory could be restored. 

To test this hypothesis, scientists began by determining the memory disparity between 6-month-old mice and 20-month-old mice. Both groups were individually placed in a maze with various objects located throughout; each mouse was repeatedly sent through the maze to determine if they could remember the objects. As expected, the older mice displayed significantly less memorizing abilities than the younger mice. The second phase of the experiment was put into motion when the 20-month-old mice were administered a viral vector₃ that would increase the level of chondroitin 6-sulphate in their perineuronal nets. After sending the older, treated mice and the younger, untreated mice through the maze again, the results produced were astonishing. The memory of the older mice was found to be nearly equivalent to that of the younger mice. 

Although the implications of these findings are not completely understood, they may prove to become significant contributions to the field of neuroscience. Many structures in the brains of mice are similar to those in humans, including the ones tested in the study, which means that these results could potentially be replicated in people. While it is unknown how the treatment may affect Alzheimer’s disease or other diseases that impact memory, it is possible that the viral vector increasing C6S could mitigate memory loss resulting from age.

 

Plasticity₁the adaptability of an organism to changes in its environment or differences between its various habitats.

Neuroplasticity₂the ability of the brain to form and reorganize synaptic connections, especially in response to learning or experience or following injury.

Viral Vector₃Viral vectors are tools commonly used by molecular biologists to deliver genetic material into cells.

 

Citations:

Yang, S., Gigout, S., Molinaro, A. et al. Chondroitin 6-sulphate is required for neuroplasticity and memory in ageing. Mol Psychiatry (2021). https://doi.org/10.1038/s41380-021-01208-9

Fawcett, J.W., Oohashi, T. & Pizzorusso, T. The roles of perineuronal nets and the perinodal extracellular matrix in neuronal function. Nat Rev Neurosci 20, 451–465 (2019). https://doi.org/10.1038/s41583-019-0196-3

Website with summarized information:

https://www.leeds.ac.uk/news-science/news/article/4881/scientists-reverse-age-related-memory-loss-in-mice