Control of oxidative stress
Free radicals (Reactive Oxygen Species, ROS) are substances that have only one electron on their surface. Free radicals are very unstable molecules and in their attempt to acquire a stable structure, “steal” electrons from adjacent substances, which however, are converted into free radicals. This way, a chain reaction begins, that disrupts cellular balance and function.
In many cases free radicals are formed and cause oxidative stress in cells. Common causes include conditions such as obesity, varicocele, various endocrine or metabolic diseases and chronic inflammation of the male genital tract, or habits such as smoking or substances of abuse.
Free radicals, when present in a sperm sample in low concentrations, are essential for the proper functioning of the male reproductive system and the processes performed in it, including spermatogenesis. However, increased concentrations impair the normal function of the spermatozoa. A cell, in order to protect itself from oxidative stress, develops antioxidant mechanisms. The spermatozoon has limited levels of antioxidant defense and lacks a mechanism that would allow it to accurately detect and repair damage. Consequently, sperm cells are particularly vulnerable to oxidative stress.
Free radicals can cause:
1.changes in the structure of proteins and
2.extensive damage to sperm cell DNA.
These changes consequently reduce the fertilizing capacity of a sperm sample, making it difficult for a couple to conceive naturally or with assisted reproduction techniques such as insemination or IVF. Oxidative stress is also considered to be one of the causes of recurrent miscarriages.
Recently, checking oxidative stress has become part of the routine of male fertility tests. The 8-OHdG test in spermatozoa is a scientific laboratory technique, which is not based on a commercial kit and was developed many years ago. It is popular in many laboratories worldwide and is supported by many years of reliable literature. The method is based on the calculation of the levels of 8-OHdG (8-hydroxy-deoxyguanosine) which is a product of DNA degeneration. Guanosine will be converted to 8-hydroxy-deoxyguanosine when oxidative stress is generated that exceeds the antioxidant capacity of the cell. The detection method is based on flow cytometry. The ability of the flow cytometer to evaluate a huge number of sperm cells, is another reason why this method is the most reliable.