What Does Intracytoplasmic Sperm Injection Change in Embryonic Development? The Spermatozoon Contribution

The intracytoplasmic sperm injection (ICSI) technique was invented to solve severe male infertility due to altered sperm parameters. Nowadays, it is applied worldwide for the treatment of couple infertility. ICSI is performed with any available spermatozoon from surgery or ejaculated samples, whatever are the sperm motility, morphology or quantity. The aim of the present review was to study if embryo development and kinetics would be modified by (1) ICSI under the technical aspects, (2) the micro-injected spermatozoa in connection with male infertility. From published data, it can be seen that ICSI anticipates the zygote kinetics Furthermore, because fertilization rate is higher in ICSI compared to conventional in vitro fertilization (IVF), more blastocysts are obtained for clinical use in ICSI. Sperm and spermatozoa characteristics, such as sperm parameters, morphology and vitality, DNA content (levels of sperm DNA fragmentation, microdeletions, and chromosomal abnormalities), RNA content, epigenetics, and sperm recovery site (testicular, epididymis, and ejaculated), have an impact on fertilization and blastocyst rates and embryo kinetics in different ways. Even though ICSI is the most common solution to solve couples' infertility, the causes of male infertility are crucial in building a competent spermatozoa that will contribute to normal embryonic development and healthy offspring.

Automated summary

The intracytoplasmic sperm injection (ICSI) technique was invented to address severe male infertility caused by altered sperm parameters. It is now widely used worldwide for couple infertility treatment. ICSI can be performed using any available spermatozoon, regardless of motility, morphology, or quantity. Published data shows that ICSI accelerates zygote kinetics and leads to higher fertilization rates and more blastocysts for clinical use compared to conventional IVF. Various sperm and spermatozoa characteristics, such as parameters, morphology, vitality, DNA content, RNA content, epigenetics, and recovery site, have different impacts on fertilization, blastocyst rates, and embryo kinetics. While ICSI is the most common solution for couple infertility, understanding the causes of male infertility is crucial for producing competent spermatozoa that contribute to normal embryonic development and healthy offspring.