Smoking cigarettes is generally accepted as
being bad for us and there are lots of studies around second-hand smoking,
though the term “passive” is probably a better descriptor. There are a large
number of conditions that are a problem due to cigarette smoke in addition to
heart and lungs.
Apparently
it appears to be a factor in the development of Alzheimer’s and dementia. There
appears to be some evidence for it being a risk factor for cognitive decline in
that it may enhance the rate of decline. Ho et
al decided to tackle this from the neuropathology angle to get a measure of
the chemical and structural changes that can occur in the brain of chronic
smokers. Their results are published in the Public Library of Science (1).
The
chronic (passive) smokers in this case were 5 rats who jointly (so to speak)
were consuming 12 cigarettes in a one-hour session held every day for 56 days.
The preferred smoke was filter tip Camels, but like most passive smokers, they
didn’t get a choice of brand. There were also 4 rats who ran around in nice
clean air for that same hour and were the control group.
There
was no cognitive testing of our rodent friends, but each one had its brain
examined. In a great deal of detail, I should add. The results were quite clear
with signs of oxidative stress in the hippocampus of the smokers as well as a
decrease in pre-synaptic proteins.
This
is bad news as we all want our synapses to give us increasing connectivity. The
spikyness of the neurons was also decreased. These two things look like a
decrease in plasticity, that is a sign of cognitive decline. Other proteins
were also affected. All in all the synaptic decline was indicating the path of
a neurodegenerative condition.
There
was no sign of senile plaque and the authors point out that smoking is only one
risk factor for Alzheimer’s. Anyway 56 days for chronically smoking rats is
quite a short time.
I
feel compelled to wonder if, after that short time, were they hooked? And given
the choice, would they have opted for a patch or chosen to go cold turkey if
the dangers of signing up for this experiment had been explained to them?
