Stress levels of fathers at preadolescence or as adults greatly affect the brain development of their children, a latest study reveals.
In order to find how the stress levels of man could affect his children, researchers at University of Pennsylvania performed the study on male mice. They exposed the mice to various types of chronic stress such as sudden cage movement, introduction of an unfamiliar object, predator odor and strange noise. The stress was put on the mice before breeding when they were in their puberty or already into their adulthood.
The researchers found that stress in adult male mice had a genetic effect that reprogrammed the offspring's hypothalamic-pituitary-adrenal aix or HPA, a part of brain that controls reactions to stress.
The offspring of the mice showed blunted levels of stress hormone, corticosteron, after being put in such situations. This means that the offspring did not respond to stress well which can have positive and negative side effects. "It didn't matter if dads were going through puberty or in adulthood when stressed before they mated. We've shown here for the first time that stress can produce long-term changes to sperm that reprogram offspring brains," said lead researcher Tracy Bale. She further said that paternal stress may be linked to neuropsychiatric diseases.
Surprisingly, both male and female offspring had abnormally low reactivity to stress. The researchers further found that the two regions in the brain of the offspring had changed stress regulation. The researchers examined a series of microRNAs (miRs) located in the sperm that is responsible for offspring gene expression post-fertilization. They found that in miRs the expressions were increased.
"Whether such diminished stress reactivity would be detrimental or beneficial to offspring likely depends on the environment into which they were born, as well as genetic background factors," Bale said.
