Dead spermatozoa in raw semen samples impair in vitro fertilization outcomes of frozen-thawed spermatozoa

A high proportion of dead spermatozoa in raw semen samples increases the generation of endogenous reactive oxygen species and nuclear DNA fragmentation when frozen-thawed, impairing IVF ability and embryo development.

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Jordi Roca, Ph.D., Maria J. Martinez-Alborcia, D.V.M., Maria A. Gil, Ph.D., Inmaculada Parrilla, Ph.D., Emilio A. Martinez, Ph.D.

Volume 100, Issue 3, Pages 875-881, September 2013



To evaluate the influence of dead spermatozoa present in raw semen samples before and during freezing on the functionality and fertilization ability of frozen-thawed spermatozoa.


Cryopreservation of raw semen samples with different known proportions of dead spermatozoa: native semen samples (<10%) and samples with 25%, 50%, and 75% dead spermatozoa. Setting:

A university-based veterinary andrology laboratory.


Five healthy and sexually mature boars.


Sperm killed by three fast-freezing cycles.

Main Outcome Measure(s):

Assessment of intracellular generation of reactive oxygen species (ROS), nuclear DNA fragmentation, in vitro fertilization (IVF), and embryo development.


High proportions of dead spermatozoa in raw semen samples before and during freezing induce statistically significantly increased ROS generation and nuclear DNA fragmentation in frozen-thawed spermatozoa. These dysfunctional changes resulted in low ratios of in vitro penetrated oocytes and healthy developing embryos.


A high proportion of dead spermatozoa present in raw semen samples before and during freezing negatively influences the functionality and IVF outcomes of frozen-thawed spermatozoa.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders. The journal publishes juried original scientific articles in clinical and laboratory research relevant to reproductive endocrinology, urology, andrology, physiology, immunology, genetics, contraception, and menopause. Fertility and Sterility® encourages and supports meaningful basic and clinical research, and facilitates and promotes excellence in professional education, in the field of reproductive medicine.