Nerve cells transplanted into brain-damaged rats helped them fully recover their ability to learn and remember, probably by promoting nurturing, protective growth factors, a new study in India has found.
The study confirmed that cell transplants could help the brain to heal itself.
It is believed that the discovery could lead to new therapies to help dementia patients.
In fact, scientists can now develop and test new ways to help repair an injured nervous system-whether through new drugs, genetically modified cells, transplanted neural (nerve) and non-neural brain cells, or other means.
The authors claimed that the findings confirmed the potential of cell grafts to stimulate the release of growth factors for neurons, regenerate or reorganize a part of the brain, and restore cognitive function, in a process called neural plasticity.
This study focused on the hippocampus, considered to be the seat of learning and memory, whose shrinkage in Alzheimer's disease causes steadily worsening symptoms.
The researchers targeted a key player in the hippocampal "learning system," which includes the hippocampus itself, the subiculum (the major output structure connected to the cortex, the self-aware "thinking" part of the brain), and the adjacent entorhinal cortex.
Previously, these scientists had demonstrated that damage to the subiculum in rats led to deterioration of the hippocampus, and problems with learning.
But they wanted to do the opposite-repair the hippocampus and restore the memory functions.
And thus they conducted the study at India's National Institute for Mental Health and Neuro Sciences and National Centre for Biological Sciences (Tata Institute for Fundamental Research), both in Bangalore.
For the study, scientists injected a neuron-destroying chemical into the subiculum area of 48 adult rats.
Next, again using precise micro-injections, the scientists transplanted hippocampal cells that had been taken from newborn transgenic mice and cultured in an incubator into the hippocampi of about half the rats.
They found that the rats given cell transplants had recovered completely, while those without transplants did not recover.
The researchers observed that transplants can provide more neural growth factors in the hippocampus, because the formation of new neurons there may be critical for cognitive function.
The study has been published in the December issue of Behavioural Neuroscience, published by the American Psychological Association.