Prolonged fear and anxiety due to stressors just like the novel coronavirus (COVID-19) pandemic not only takes a toll on an individual's psychological state but even has an enduring impact on sperm composition that would affect the future offspring, warn researchers.
The study, published in the journal Nature Communications, outlines a biological mechanism for a way a father's experience with stress can influence fetal brain development in the womb.
According to the researchers, the consequences of paternal stress are often transferred to offspring through changes in the extracellular vesicles that then interact with maturing sperm. Extracellular vesicles are small membrane-bound particles that transport proteins, lipids, and nucleic acids between cells.
They are produced in large amounts within the reproductive tract and play an integral role in sperm maturation.
"Properly managing stress can not only improve mental health and other stress-related ailments, but it can also help reduce the potential lasting impact on the reproductive system that could impact future generations," said study researcher Tracy Bale from University of Maryland in the US.
To examine a completely unique biological role for extracellular vesicles in transferring dad's stress to sperm, the researchers examined extracellular vesicles from mice following treatment with the strain hormone corticosterone.
After treatment, the extracellular vesicles showed dramatic changes in their overall size also as their protein and littleRNA content.
When sperm were incubated with these previously "stressed" extracellular vesicles before fertilizing an egg, the resulting mouse pups showed significant changes in patterns of early brain development, and as adults these mice were also significantly different than controls for a way they skilled stress themselves.
To see if similar differences occurred in human sperm, the researchers recruited students to donate sperm monthlyfor 6 months, and complete questionnaires about their perceived stress state within the preceding month.
They found that students who had experienced elevated stress in months prior showed significant changes within the small RNA content of their sperm, while those that had no change in stress levels experienced little or no change.
These data confirm a really similar pattern found within the mouse study.
"Our study shows that the baby's brain develops differently if the father experienced a chronic period of stress before conception, but we still do not know the implications of these differences," said Bale.
According to the researchers, stress-induced changes within the male genital system happen a minimum of a month after the strain is attenuated and life has resumed its normal patterns.
"It is important to realize that social distancing does not have to mean social isolation, especially with modern technologies available to many of us," said Joshua Gordon, Director of the National Institute of Mental Health in his web message about coping with coronavirus.
"Connecting with our friends and loved ones, whether by high tech means or through simple phone calls, can help us maintain ties during stressful days ahead and will give us strength to weather this difficult passage".