ADVANCED SPERM SELECTION TECHNIQUES FOR ASSISTED REPRODUCTION

 

Sperm selection for use in assisted reproduction techniques is performed to extract quality sperm from the semen which does not only contain nutrients for the sperm, but also bad-quality sperm, white blood cells, and many other cell particles. Moreover, the Reactive Oxygen Species (ROS) and Prostaglandins (PG) are also contained in the semen. Too much of ROS will result in sperm DNA damage as the capacitation process is disrupted and sperm is left without the ability to fertilize. Prostaglandins trigger muscles in female uterus to contract. Excessive amount of PG can cause reduced blood flow in uterus and sharp pain. Sperm selection, therefore, is meant to ensure the quality of sperm under a proper environment that is ideal for fertilization. Sperm selection techniques vary based on the quality and the number of sperm. Common techniques are explained as follows:

 

1.Swim Up – By this technique, the sperms are selected on their motility and the capability to swim out of the seminal plasma. The swim up results in sperm with good motility and less contamination. It is preferred if the semen sample has a normal number of good sperms (spermatozoa).

 

2. Gradient Separation – By this technique, semen is centrifuged through solutions with different density level. Live sperms have high cell density and can pass through the solutions, while dead sperms, white blood cells, and other cell particles are suspended.

 

3. Simple Washing – By this technique, semen is diluted in a test tube, with a special solution of antibiotics and protein supplements. It is then placed in a centrifuge, a machine that spins around at extremely high speeds. It is preferred only when semen has a very small number of sperms. In addition, a new technique ‘Magnetic-activated cell sorting’ (MACS) is a method that can separate sperms with apoptosis from good sperms through a magnetic field. This technique results in sperms with perfect cell membrane, normal mitochondria, no apoptosis, and reduced DNA fragmentation. Sperms separated with MACS are found to have a higher fertilization rate and blast rate, compared to other techniques. This significantly increases the success rate for assisted reproduction. This new technology is recommended for semen with high DNA fragmentation (DNA fragmentation index higher than 25%) which can be checked with Sperm DNA Fragmentation Test as apoptosis process is related to DNA fragmentation. Therefore, selecting the right sperm-screening method is a crucial step in the treatment process, increasing the success rate for the patient.