In the animal kingdom, size usually equates to longevity: elephants and whales can live for about 70 years ; a common mouse, two. In the world of dogs , the opposite happens. The blame could be on free radicals, according to research by a team of students at Colgate University in Hamilton, New York.
Oxygen free radicals arise as a waste from the process by which cells obtain energy from food. They are molecules that have lost electrons and try to recover them by “stealing” them from the body’s cells, damaging them (“oxidizing” them) in the process. The body generates antioxidant molecules that neutralize these harmful agents, but the more energy an organism produces, the more free radicals escape to do damage.
This metabolic process seems to be one of those responsible for the aging and deterioration of the body, and could explain why large dogs tend to die earlier than smaller ones.
Live fast and leave a pretty corpse
To test this hypothesis, Colgate University researchers Josh Winward and Alex Ionescu collected 80 tissue samples from puppies and old, recently dead dogs, large and small breeds. They isolated cells from these remains and cultured them in the laboratory for analysis.
They found that in the cells of adult dogs of both types, the production of energy and free radicals was balanced. In those of the bulky hatchlings, things changed: the rate of oxygen free radicals skyrocketed, and the antioxidants couldn’t stop them. This happens because large breed puppies have fast metabolisms that consume much more energy than small puppies. Such an imbalance produces cellular damage that manifests itself in a few years and shortens the life of the animals.
There are other reasons for canine aging , but oxygen free radicals seem to play a key role. According to Winward, knowing how these molecules work will help to develop nutritional supplements with antioxidants for large breed puppies that eliminate radicals before they do damage.
