In Vitro Fertilization Techniques in Mammalian Reproductive Biology

In vitro fertilization (IVF) in mammals encompasses a series of coordinated steps that replicate the natural union of gametes outside the body. Following ovarian stimulation and oocyte retrieval, spermatozoa undergo capacitation and selection to ensure motility and fertilising competence. Gametes are co-incubated under controlled conditions to promote acrosome reaction and fusion with the zona pellucida of the oocyte. Resulting embryos are cultured through cleavage stages before transfer into a receptive uterus. Advances in cryopreservation enable long-term storage of spermatozoa and embryos, facilitating genetic archiving and global distribution of valuable lines. Recent innovations span microfluidic sorting, novel cryoprotectants and modified culture media, all aimed at boosting fertilisation rates, embryo viability and developmental competence. These techniques are applied across research models—from mice and rats to livestock species—and underpin progress in genetics, conservation biology and assisted reproduction in human infertility clinics.

Research from Nature Portfolio

Microfluidics-based cell sorting has been adapted to select mouse sperm with minimal mechanical damage, using acrosome reaction markers to enrich fertilisation-prone subpopulations. This approach yields higher fertilisation rates in standard IVF assays and supports normal embryo development post-transfer. In the rat model, newly optimised protocols for cryopreservation of transgenic sperm and subsequent IVF have been established, delivering consistently high fertilisation rates and offering a robust platform for genome-edited strain maintenance. An ‘easy and quick’ freezing method for mouse cauda epididymides permits one-step storage at –80 °C, producing practical fertilisation rates after thawing and enabling transfer to liquid nitrogen for indefinite archiving. This simple protocol safeguards against sudden facility closures and reduces reliance on specialised containers or expertise.

In Vitro Fertilization Techniques in Mammalian Reproductive Biology publication trend

The graph below shows the total number of articles in in vitro fertilization techniques in mammalian reproductive biology across all publications each year (not limited to Nature Index journals).

Technical terms

In vitro fertilization (IVF): Laboratory procedure in which oocytes and capacitated spermatozoa are co-incubated to achieve fertilisation outside the organism.

Cryopreservation: Process of freezing and storing cells or tissues at ultra-low temperatures to maintain viability over time.

Capacitation: Biochemical and physiological changes sperm undergo in vitro or in vivo to gain the ability to penetrate the oocyte.

Acrosome reaction: Release of enzymes from the sperm head essential for penetration of the oocyte’s zona pellucida.

Microfluidics: Technology that manipulates small fluid volumes in channels to sort or select cells based on physical or chemical properties.

Reactive oxygen species (ROS): Chemically reactive molecules that, in excess, inhibit sperm function but can be mitigated by antioxidants.

References

1. Conserving, Distributing and Managing Genetically Modified Mouse Lines by Sperm Cryopreservation. PLOS ONE (2008).
2. Inhibition of In Vitro Fertilizing Capacity of Cryopreserved Mouse Sperm by Factors Released by Damaged Sperm, and Stimulation by Glutathione. PLOS ONE (2010).
3. Successful selection of mouse sperm with high viability and fertility using microfluidics chip cell sorter. Scientific Reports (2020).
4. Graphene Oxide Improves in vitro Fertilization in Mice With No Impact on Embryo Development and Preserves the Membrane Microdomains Architecture. Frontiers in Bioengineering and Biotechnology (2020).
5. Establishment of sperm cryopreservation and in vitro fertilisation protocols for rats. Scientific Reports (2020).
6. A simple and economic protocol for efficient in vitro fertilization using cryopreserved mouse sperm. PLOS ONE (2021).
7. Easy and quick (EQ) sperm freezing method for urgent preservation of mouse strains. Scientific Reports (2021).