Poster Presentation ESA-SRB-ANZOS 2025 in conjunction with ENSA

SIRT1 overexpression in female mice results in an increase in blastocyst cell numbers following IVF (128461)

Georgia A Bennett 1 , Shannon P Smyth 1 , David K Gardner 1 2 , Elizabeth G Bromfield 1 3 4
  1. School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
  2. Melbourne IVF, Melbourne, VIC, Australia
  3. Centre for Reproductive Science, University of Newcastle, Newcastle, NSW, Australia
  4. Infertility and Reproduction Research Program, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia

Aims: Sirtuins are a class of NAD-dependent deacetylases that have been implicated in

regulating longevity and oxidative stress, with SIRT1 being of interest in regulating oocyte

quality(1, 2). The success of IVF treatment is correlated with female age and related

oxidative stress. This study aimed to (1) investigate the ability for SIRT1 overexpression in mice

to protect oocytes against oxidative stress and (2) evaluate the impact of SIRT1 overexpression

on IVF embryo development.

 

Methods: Oocytes were collected from 4–7 week-old SIRT1super hemizygous overexpression

(SIRT1super) and wild type mice following superovulation. Total oocyte numbers and stages

were recorded in response to superovulation. IVF was conducted with wild type sperm and

resulting embryos were cultured for 4.5 days. The impact of SIRT1 overexpression on embryo

development and quality was analysed using H2DCFDA to measure reactive oxygen species

(ROS) production in untreated and 25µM hydrogen peroxide (H2O2) treated embryos at 8-

cell/morula stage. Differential nuclear staining was performed to assess cell allocation in

blastocysts.

 

Results: Blastocysts derived from SIRT1super mice had significantly more cells in their

trophectoderm (87.87±3.0 vs 97.69±2.5, P<0.05; n>60) and total blastocyst cell number

(112.4±3.0 vs 123.6±2.7, P<0.01; n>60) compared to wild type embryos. No difference in

fertilisation, 2-cell or blastocyst rates and in the total number of oocytes ovulated per

mouse was determined, however SIRT1super mice ovulated fewer mature MII oocytes

(78.12±3.9 vs 67.85±3.5, P<0.05; n=8 biological replicates). There was no significant difference in intracellular

ROS between SIRT1super and wildtype embryos. However, a trend towards decreased

sensitivity to H2O2 was observed for SIRT1super embryos, suggesting further experiments are

needed to understand this response.

 

Conclusion: SIRT1super mice produce blastocysts with significantly higher cell numbers

compared to wild type. They do however, ovulate fewer mature oocytes following

superovulation. These data suggest that modulating SIRT1 is beneficial in improving IVF

embryo quality.

  1. Di Emidio G, Falone S, Vitti M, D'Alessandro AM, Vento M, Di Pietro C, et al. SIRT1 signalling protects mouse oocytes against oxidative stress and is deregulated during aging. Hum Reprod. 2014;29(9):2006-17.
  2. Tatone C, Di Emidio G, Barbonetti A, Carta G, Luciano AM, Falone S, et al. Sirtuins in gamete biology and reproductive physiology: emerging roles and therapeutic potential in female and male infertility. Hum Reprod Update. 2018;24(3):267-89.