What is Sperm selection and separation?
In the ART (artificial reproductive technology) industry, collection of semen is a major factor. What is even more important is the assessment and separation of the semen with regard to quality – and separating the high level spermatozoa from the low quality for use in ART treatments.
For this purpose, the male partner is requested to provide a semen sample. This is usually done by an ejaculate sample obtained by himself through masturbation. Generally, the person is asked to abstain from ejaculation for 2-5 days prior to the semen collection. Use of lubricants, saliva and jellies is not allowed as they may contain toxins harmful to the sperm.
A semen analysis is done to measure sperm quantity, quality (including motility and morphology) among other aspects. Usually, in infertile men, sperm samples are found to have either abnormal morphology (size and shape), poor motility (slow or no movement), low concentration, azoospermia (absence of sperm) and DNA damage.
Also, high levels of ROS (reactive oxygen species) are found in many semen samples of infertile men. This causes less motility, decreased DNA integrity and other defects caused by oxidative stress from ROS and less antioxidants to neutralise ROS. Low ROS levels are required for certain physiological sperm functions such as sperm capacitation (changes required to be able to penetrate and fertilise an egg), acrosome reaction (the process of reaction in the acrosome – the cap like structure over the anterior part of the sperm’s head – as it approaches the egg) and hyperactivation (the movement pattern at the site and time of fertilization).
Hence the assessment of sperm as the initial step and then separation or selection of sperm cells plays an essential role in isolating the high quality sperm to be used in ART treatments.
Separating the healthy sperm from the rest which may contain immotile sperm, sperm with poor DNA integrity, proteins, enzymes and fluids which can be harmful for fertilisation ensures that only the high quality sperm is available.
The sorting of sperm cells is helpful because it is a natural way to isolate the vibrant cells from somatic cells and semen debris. It can also separate them from damaged and dead sperm cells. A high motility rate is required for successful fertilisation. Separating the high quality, high motility sperm from the low quality ensures that only the best spermatozoa is available for use.
Low quality sperm DNA integrity could lead to unexplained failed fertility treatments, recurrent and early loss of pregnancy. This sperm DNA integrity can be detected by diagnostic tests.
These are some of the reasons why sperm collection, separation and isolation is so important. We, at Andrology Center, offer both the semen analysis and sperm DFI (DNA fragmentation index) tests, which help with the measurement of sperm quality.
There are various methods and techniques by which sperm selection can be done. We explain more in our next blog.