NEWS & KNOWLEDGE

Preparing sperm for maximum efficiency is important in increasing pregnancy rates. Choosing a method for preparing semen before using it for assisted reproductive technology. This may be determined by the quality and quantity of the semen sample. At present, it is popular to use a combination of Density gradient centrifugation and Swim up methods because the amount of motile sperm and very normal sperm are obtained.

The popular methods used to prepare sperm are divided into 5 methods as follows:

1. Density gradient centrifugation (DGC)

It is a popular sperm selection method. To be used for artificial insemination (IUI), in vitro fertilization (IVF), or ICSI by preparing sperm. The objective is to separate normal sperm from semen (seminal plasma) because in semen, in addition to sperm, there are also white blood cells. dead sperm and other cellular debris, prostaglandins and to eliminate things that may be harmful to sperm, such as bacteria or free radicals, reactive oxygen species (ROS).

The solution used to prepare it has silane coated silica as a component. Based on the principle of solution density. to allow substances with higher densities to pass through the layer of substances Living sperm has a high cell density. Therefore, it can pass through the layer of silane coated silica. Dead sperm and other cells have low cell densities. Therefore cannot be spun through the solution layer.

Density gradient centrifugation method You will see the separation of the lower phase 90% and upper phase 45% solution, followed by the semen layer. After spinning, the semen plasma portion remains at the top. This is followed by a layer of white blood cells and other cellular debris. Next is a layer of immobile sperm. The bottom layer is the layer of living sperm.

2. Simple washing

It's a quick and easy way to get a lot of sperm. But it is not recommended for general use. Due to the spinning of semen with the culture solution. without separating good sperm from white blood cells and dead sperm Can cause oxidation reactions. which will destroy the quality of sperm This method is suitable for cases where there is very little sperm. until it was not possible to prepare using the density gradient method.

3. Direct swim-up

It is a sperm selection technique based on the sperm's ability to swim out of the seminal plasma into the culture solution layer. Used to separate moving sperm from inactive sperm. This can be done by using a pipette to drop the culture solution over the semen. Or use a pipette to leave the semen at the bottom of the tube under the culture solution. Then tilt it at 45 degrees and leave it in the incubator at 37 degrees Celsius. The moving sperm will swim up to the layer of the culture solution. This method will produce less sperm than the simple washing method, but it will help in selecting groups of sperm that have good motility. This is useful in patients with low sperm motility rates.

4. Magnetic Activating Cell Sorting (MACS)

MACS sperm or MAC ART annexin V system is a technique that improves the quality of sperm preparation for use in assisted reproductive technology. Normally, sperm ejaculated will contain both live sperm. Moves well and dead sperm or poor movement mixed together Poor quality sperm secretes oxygen free radicals. Causes bad effects on surrounding cells.

The MACS sperm technique is a method of selecting healthy and perfect sperm. By using the principle of dead or damaged sperm (apoptotic sperm), the cell surface will change its properties, causing substances. phosphatidylserine (PS) moves out to the cells covering the outer sperm surface. which can bind to annexin V well, dead or damaged sperm The skin's covering cells will change its properties, causing it to contain substances. phosphatidylserine Move out to the cells covering the outer surface of the sperm.

Annexin V reagent and phosphatidylserine (PS) bind together in apoptotic sperm.

Sperm binds to annexin V via a magnetic field. The dead sperm is captured by the magnetic field. Healthy sperm (viable spermatozoa) can pass through a magnetic field (left) and the process of magnetic separation is shown (right).

5. Microfluidic sperm sorting

Microfluidic sperm sorting is the selection of sperm by using the properties of the sperm itself. using specially developed selection equipment Reduce sperm cycling This may cause damage to the sperm DNA. The equipment used in the selection It is a disposable microfluidic sperm sorting device which was developed by allowing sperm to run from one point to another, such as selecting sperm that run against the flow of water. or selected by passing obstacles Divided into many small alleys that sperm can run through until they reach their destination. Therefore it is a strong sperm. Sperm that stays in place or doesn't move Will be stuck at the sperm release point, unable to reach the destination.

How to prepare this sperm Get sperm with a low rate of DNA breakage and good sperm motility. But there is a disadvantage. Got a small amount of sperm Not suitable for use for intrauterine injection (IUI).

By:

 Assoc.Prof. Matchuporn Sukprasert

Piyarat Sopaboon, Clinical Embryologist