DNA damage in sperm and heat exposure

Guys, we’ve posted previously about the impact tight underwear can have on sperm and why sitting with a laptop on your lap may be detrimental to your fertility and generally not a great idea.

Now, biologists from the University of Oregon have used a model organism to help identify the molecular mechanisms involved with DNA damage and how this impacts the quality of your sperm.

Ideally, in humans, the optimal temperature for sperm is slightly below body temperature, which is why the scrotum is located on the outside of the body. This is why, when we ask you to complete the form at the time you provide your semen sample, we ask if you have been unwell in any way – having a fever can raise your body temperature high enough to damage sperm production and impact the quality of your sperm.

Up until now, the underlying mechanisms associated with sperm damage have not been completely understood. Scientists used a species of roundworm as a biological model to observe the effects of small fluctuations in temperature and discovered that an increase of 2°C was enough to increase the level of DNA damage 25-fold. Subsequentially, eggs that were inseminated with this sperm either failed for fertilise or didn’t produce offspring.

Sperm is the smallest cell in the human body and are incredibly sensitive to increased temperatures, whereas human eggs are the largest cells in the human body and are formed internally where there the temperature is consistent. Data presented in this paper has suggested that sperm and eggs also differ in the way they control mobile DNA elements (sequences that can change position within a genome and sometimes create or reversing mutations). These DNA elements are sensitive to heat stress and when exposed to increased temperatures, these elements become mobile in developing sperm.

So, what does this mean?

Essentially, this means that even a small rise in temperature can create errors within meiotic divisions and result in damaged sperm.

Fertility First offers patients the option of the Halosperm assay which is used to assess the fertility potential of sperm by determining the percentage of sperm that contain fragmented and damaged DNA. The Halosperm assay provides invaluable information about the quality of the DNA inside the sperm’s chromosomes and helps to provide clinical diagnosis and the management of male infertility.

For more information or to make an appointment contact the clinic for more details on (02) 9586 3311.