Oxidative stress is the leading cause for DNA damage in the sperm and it can have a long-term effect in male fertility. Reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), hydroxyl radicals (OH-) and superoxide anions (O2-), are normally present in the semen as byproducts of sperm activity. ROS are maintained at low levels by effective anti-oxidant mechanisms, and at health, their fine-balanced levels benefit the process of fertilization.
However, if ROS rise, they cause oxidative stress and an array of effects depending on the level of their increase. They can:
- affect the sperm cell membrane changing its shape
- decrease sperms’ ability to produce the required energy for swimming fast and efficiently
- cause sperm DNA fragmentation
- reduce sperm vitality
- diminish overall testicular function, sperm production and maturation
Increased ROS levels are associated with male infertility and poor-outcome Assisted Reproductive Technique (ART). If a successful insemination takes place, oxidative stress can also affect normal embryo development.
In case you are diagnosed with high ROS levels, a DNA fragmentation test assessing the genetic integrity of your sperm will be recommended, as it can show us the extent of the problem.
This test can provide answers to men that have faced an infertility issue for a long time. A classical semen analysis may show the effects of oxidative stress in sperm quality and quantity, but it will not reveal the reason behind it.
This test is also informative if you had a previous failed ART, experienced repeated miscarriages, or if your case has been linked to unexplained infertility.
Elevated ROS can be the result of an immune response and inflammation due to a genito-urinary tract infection, a sexual transmitted disease, injury, surgery, or due to a chronic condition. Furthermore, it can be caused by chemical, toxic or radiation exposure (including treatment for cancer), cigarette smoking, high alcohol or drug consumption and medical conditions, such as varicocele or cryptorchidism.
Sperm production in the testes is a continuous process, with a sperm maturation cycle taking about 11-12 weeks. Managing the above risk factor(s) and enriching your nutrition with anti-oxidants can reduce the levels of ROS in your sperm within a period of 3-6 months. In case of an infection or other medical condition, antibiotic treatment or corrective surgery (as with varicocele for instance) can also decrease ROS levels.
A repeat semen analysis in conjunction with oxygen stress testing will show the improvement. However, if the cause is a chronic condition, ROS levels may remain irreversibly high.
Oxidative stress testing is done by one of our andrology technologists in the laboratory following sperm collection for analysis.
After initial stages of semen preparation, which include semen washing and centrifugation for the collection of sperm, the sample is allowed to reach liquefaction (the ability of semen to turn from the gel-like state of the ejaculate into a liquid state). Following, a chemical that emits light (chemiluminescence) when bound to a ROS byproduct is added to the sample. The color produced depends on the amount of ROS in the sample, and is measured by the use of an apparatus called a luminometer. The results are compared to a range of standard ROS values and presented as amount of ROS per total number of sperms in a sample.
A big percentage of infertile men suffer from oxidative stress, and as high levels of ROS can severely affect sperm quality and quantity, the success rate of an ART-mediated conception for untreated cases is low.
With efficient management of risk factors and a diet rich in anti-oxidants, ROS levels can drop increasing the chance of a successful ART (especially when other parameters, such as maternal age and egg quality are also optimal).
In straightforward cases, after effective treatment, a natural conception may even become possible. However, in more challenging cases, in which sperm DNA fragmentation has occurred, the success of an ART cannot be guaranteed.
Here in AAFC, we use the sperm oxidative stress test in conjunction with other diagnostic tests in order to understand persistent infertility, previous ART failure and repeated miscarriages. We can help you take an informed reproductive decision and offer you support, when necessary. Our specialist doctors will provide you with a comprehensive consultation for all other available / applicable options and explanations.