Sperm cultivation is an essential process in assisted reproductive technologies (ART) to help fertilize eggs for couples struggling with infertility.

Optimizing sperm cultivation can increase the success rate of fertilization, which ultimately leads to higher success rates of ART. This article discusses various techniques and practices that can be adopted to optimize sperm cultivation and enhance the success rate of ART.

The Importance of Sperm Culture

Sperm culture is a process of providing a nutrient-rich environment to the sperm for their growth and maturation. Culture media are typically used for this purpose, which contains various components essential for their growth and development.

The sperm culture process is carried out mainly for three reasons – preservation, selection, and fertilization.

Preservation Techniques

Preservation of sperm is a necessary criterion in ART to promote successful fertilization. There are various preservation techniques that can be adopted to retain the quality and motility of sperm even after long-term storage. These include:.

Cryopreservation: Cryopreservation is a well-established technique for preserving sperm for a longer duration. Sperm is frozen rapidly, with the help of liquid nitrogen, at a temperature of -196°C. This method has been shown to preserve the quality of sperm for up to 20 years, without any significant decrease in motility or fertilization potential.
Vitrification: Vitrification is another method for sperm preservation that involves rapid freezing in a small volume of liquid nitrogen at a temperature of -196°C. This method has been proved to be effective in preserving both motility and fertilization potential of sperm for a long period.
Slow freezing: Slow freezing is a technique that involves freezing sperm slowly and gradually up to -80°C with the help of a freezing machine. This method is not as effective as the rapid freezing techniques and requires a specialized freezing machine, making it less preferred among the ART practitioners.

Selection Techniques

Selection of high-quality sperm with good motility is essential for higher success rates in ART.

Various techniques such as density gradient centrifugation, swim-up technique, and magnetic-activated cell sorting (MACS) are used for the selection of healthy sperm.

Density gradient centrifugation: This technique involves the separation of the sperm from the seminal plasma by centrifugation using a density gradient. The high-quality sperm with high motility are then separated from other unhealthy or immotile sperm.
Swim-up technique: The swim-up technique involves placing the semen sample into a culture medium, which allows the motile sperm to swim up to the top away from unwanted components. The healthy sperm can be collected from the top layer of the medium.
Magnetic-activated cell sorting (MACS): MACS is a highly efficient technique used for the selection of healthy sperm. It involves the labeling of unhealthy sperm with magnetic nanoparticles and then separating them from healthy sperm using a magnetic field.

Fertilization Techniques

After selection, the high-quality sperm with good motility are then used for fertilization. There are two primary ways to achieve fertilization – natural selection and in vitro fertilization (IVF) techniques.

Natural selection: In natural selection, healthy sperm with good motility are directly introduced into the female reproductive tract for fertilization. This method is primarily used in intrauterine insemination (IUI).
In vitro fertilization (IVF): In vitro fertilization (IVF) is a highly effective technique used for fertilization in ART. This technique involves the removal of eggs from the female reproductive tract and the placing of sperm into a culture dish containing the egg. The sperm can then penetrate the egg, and fertilization occurs. The embryo can be implanted into the female reproductive tract once the embryo reaches a certain level of maturation.

Practices to Optimize Sperm Culture

Various practices can be adopted to optimize sperm culture and increase the success rate of fertilization. Some of the best practices are:.

Providing an optimal environment: Maintaining an optimal environment for sperm growth and development is crucial to enhancing the success rate of fertilization. Proper temperature, pH, oxygen level, and nutrient levels must be maintained in the culture dish.
Using high-quality culture media: The use of high-quality culture media with the necessary nutrients and growth factors is essential for optimal sperm growth and maturation. The culture media should be tested before use, and a single batch should be used for a specific period to ensure consistency.
Minimizing exposure to toxins: Sperm is highly sensitive to changes in the environment, and exposure to toxins can cause irreparable damage to the sperm. Therefore, sperm should be stored in a toxin-free environment with minimal exposure to chemicals and other toxins.

Conclusion

Optimizing sperm culture is an essential process in ART and can significantly increase the success rate of fertilization.

Preservation, selection, and fertilization of quality sperm, accompanied by the implementation of good practices, can optimize sperm culture and improve the chances of successful fertilization for couples struggling with infertility.