A newly-identified protein has been found to protect immature mouse sperm after they have been released into a region of the testis known as the epididymis, which is where they undergo maturation. Credit for this discovery goes yo Joel Drevet and colleagues, at Clermont Université, France.
Although male mice lacking this protein, Gpx5, had normal looking sperm and were equally as efficient as normal male mice at fertilizing female mice, an increased incidence of miscarriages and fetal developmental defects were observed when normal female mice were mated with Gpx5-deficient males over 1 year old compared with normal male mice of the same age.
Further analysis indicated that Gpx5 acts as an antioxidant in the epididymis, protecting the sperm from oxidative stress. As discussed by the authors, and, in an accompanying commentary, John Aitken, at the University of Newcastle, Australia, these data have immense clinical relevance as age-related DNA damage to human sperm has been associated with a range of adverse outcomes including decreased fertility, and increased rates of miscarriage and childhood disease.