Intracytoplasmic Sperm Injection in Male Infertility Treatment

Intracytoplasmic sperm injection (ICSI) has transformed the management of male infertility by enabling fertilisation in cases where conventional in vitro fertilisation fails. By directly injecting a single spermatozoon into the cytoplasm of a mature oocyte, ICSI bypasses many barriers associated with poor sperm motility, low sperm count or abnormal morphology. Since its introduction in the early 1990s, ICSI has become the most widely adopted assisted reproductive technology (ART) procedure worldwide, accounting for the majority of treatments in many centres. Its use has expanded beyond severe male factor infertility to include couples with unexplained infertility, previous fertilisation failure and those requiring genetic testing of embryos. Advances in micro-manipulation tools, real-time imaging and selection techniques continue to refine the procedure, improving safety and outcomes. Nevertheless, concerns over potential risks—such as subtle epigenetic effects, increased aneuploidy rates in embryos and long-term health of offspring—have driven ongoing research into optimising sperm selection, minimising oocyte trauma and understanding fundamental aspects of sperm–oocyte interaction. Globally, ICSI remains central to reproductive medicine, offering hope to millions of couples while stimulating innovation in micromanipulation systems, functional assays and embryo culture methodologies.

Research from Nature Portfolio

A novel ex vivo functional assay using amphibian egg extracts has provided fresh insights into the molecular competence of human spermatozoa. By incubating patient-derived sperm with Xenopus cytoplasmic components, researchers can now quantify processes such as chromatin remodelling and centrosome activation that are critical for early development. This system complements standard semen analysis by revealing functional deficits that correlate with fertilisation and implantation outcomes, offering a potential diagnostic tool to better stratify candidates for ICSI and to guide personalised treatment strategies.

Intracytoplasmic Sperm Injection in Male Infertility Treatment publication trend

The graph below shows the total number of articles in intracytoplasmic sperm injection in male infertility treatment across all publications each year (not limited to Nature Index journals).

Technical terms

Intracytoplasmic sperm injection: A micromanipulation procedure in which a single sperm is directly injected into the cytoplasm of an oocyte to achieve fertilisation.

Assisted reproductive technology: Clinical and laboratory methods, including ICSI and IVF, designed to overcome infertility and support fertilisation, embryo development and implantation.

Oocyte: A mature female germ cell (egg) that, upon fertilisation by a sperm, can develop into an embryo.

Hyaluronic acid binding: A sperm selection technique that exploits the natural affinity of mature spermatozoa for hyaluronic acid, aiming to choose cells with intact DNA and normal maturity.

Ex vivo assay: A laboratory test performed on cells or tissues outside the organism, here using amphibian egg extracts to assess human sperm function.

References

1. Intuitive Cell Manipulation Microscope System with Haptic Device for Intracytoplasmic Sperm Injection Simplification. Sensors (2024).
2. Thoughts on the popularity of ICSI. Journal of Assisted Reproduction and Genetics (2020).
3. Evaluation of Sperm Selection Technique Using Hyaluronic Acid Binding During Icsi; a Randomized Controlled Trial. Obstetrics Gynecology and Reproductive Sciences (2022).
4. A Simple One-Step System Enhances the Availability of High-Quality Sperm for Assisted Reproductive Procedures. Open Journal of Obstetrics and Gynecology (2023).
5. Functional Analysis of Human Pathological Semen Samples in an Oocyte Cytoplasmic Ex Vivo System. Scientific Reports (2018).