We all wish to stay healthy, but once in a while we catch something nasty. Severe bacterial infections can be very nasty and, with the increasing problem of antibiotic resistance build; we have to be careful as to permanent damage to our system, especially as we get older.
Now if we take a deep breath and leave humans and turn to lab rats we can study the longer-term damage of a severe bacterial infection without any likelihood of subsequent lawsuits. The current information is that healthy, but elderly rats, after they catch something nasty in the bacterial line and then get cured, show rather severe memory impairment. Younger rats don’t. The brain inflammation in the older critters that severe bacterial infections can cause is also severe and lasts a long time.
The long-term effects are that the ability to make new connections (plasticity) is much reduced and that a type of nerve growth factor (brain-derived neurotrophic factor, BDNF) has had its production severely curtailed. Now BDNF works in those crucial areas for memory and learning new and important stuff like finding your way through a maze, namely the hippocampus and the cortex. The hippocampus generates some neural stem cells so that we can continue to replace some neurons.
All is not lost for our furry friends. Barrientos et al from the U of Colorado have just published a solution, which will undoubtedly work for us too (1). They have found that regular exercise after the bout of nasty bacteria, increases the BDNF in the hippocampus and lo and behold those elderly rats that took daily voluntary exercise got back to their amazing maze solving, whilst their sedentary friends did not.
Of course, being elderly, the rats were skipping about rather gently and couldn’t manage more that half a mile a week. But that was sufficient. Even better though was the result that regularly exercising elderly rats didn’t have the severe neuro-inflammatory effect from a bacterial infection. So once again, we have the strong message to get out there and exercise. It may be good for the heart, but it’s even better for the brain!
- R.M. Barrientos, M.G.Frank, N.Y.Crysdale, T.R.Chapman, J.TAhrendsen, H.E.W.Dasy, S.Gampeau, L.R.Watkins, S.L Patterson & S.F.Maier, J. Neuro. Sci., 31, 11578, (2011)
