Oral Presentation The Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology 2013

Chemically elevating ROS in sperm impairs embryo development, pregnancy and offspring health similar to the male obesity phenotype. (#136)

Marni A. Spillane 1 , Deirdre Zander-Fox 1 2 , Nicole O. McPherson 1 , Tod Fullston 1 , Julie A. Owens 1 , Lauren Y. Sandeman 1 , Wan Xian Kang 1 , Michelle Lane 1 2
  1. The Robinson Institute, University of Adelaide, Adelaide, SA, Australia
  2. Repromed, Adelaide, SA, Australia

It is known that obesity can modify biochemical characteristics of spermatozoa resulting in altered metabolic health of the offspring. One of the changes observed is an increase in reactive oxygen species (ROS). This study investigated the impact of increased ROS in spermatozoa on resulting embryos, pregnancy and offspring to determine if it is a causative agent of the effects of obesity.

CBAF1 male mice (n=29) spermatozoa were extracted and exposed to control media or media containing 1500µM of H2O2 for 1h. Spermatozoa were washed and then functional parameters were determined prior to in vitro fertilisation (IVF). Embryo development (Control n=1129 embryos, H2O2 n=1152 embryos) and blastocyst cell number were assessed. Blastocysts were transferred into pseudo-pregnant Swiss mice where implantation and fetal outcomes were evaluated on day 18 of pregnancy. Additional pregnancies were carried to full term and the resulting offspring (n=38) pre-weaning weights, body composition, glucose tolerance and insulin tolerance were assessed.

H2O2 exposure did not alter spermatozoa motility, DNA damage or spermatozoa binding compared to control, however H2O2 increased intracellular ROS by 47% (P<0.01). H2O2 treatment prior to IVF resulted in delayed embryo development on day 3 (15.8% compared to 19.0% in control, P<0.05) although by day 5 blastocyst development was similar. H2O2 treatment of spermatozoa decreased the ratio of inner cell mass to total cell number (P<0.01). Female offspring weights were decreased by 15% with H2O2 treatment of father’s spermatozoa (P<0.01), while male offspring had a 35% increase in fat mass (P<0.01) at 4 weeks compared with control offspring. Furthermore, male offspring produced by H2O2 treatment had reduced insulin sensitivity at 4 weeks (-34%, P<0.05).

Treating spermatozoa with H2O2 to elevate ROS levels before fertilization partially recapitulates the offspring phenotype associated with paternal obesity, resulting in delayed embryo cleavage development, reduced fetal growth and altered body composition in offspring in a sex-specific manner.