Fertility improved, infertility 'reversed' in mice: promising new research

Pregnancy after chemo may also be a possibility
Pregnancy after chemo may also be a possibility Photo: Getty Images

The reproductive lives of mice have been extended by scientists in research that boosts the possibilities of older women, or those who have undergone chemotherapy, to conceive.

While it is early days the research team – Dr Dave Listijono and Dr Lindsay Wu at UNSW, and the University of Queensland's Professor Hayden Homer – says the results are very encouraging. Their findings were presented at the inaugural Australian Biology of Ageing Conference, hosted by the University of NSW. 

Dr Listijono said it was extremely rare for mice to reproduce after 12 or 13 months. But the mice in their study still fell pregnant at 16 to 17 months – the equivalent of the late 40s in human years.

A slide showing the improvement in egg cell quality in mice, after an extra copy of a sirtuin gene was added.
A slide showing the improvement in egg cell quality in mice, after an extra copy of a sirtuin gene was added.  Photo: UNSW

Professor Homer said "the reproductive clock for women starts ticking down after 35". But the new research suggests "there's a possibility that even when the effects of ageing have already set in, you could potentially reverse some of that".

"The aim is not to get 60-year-old women who are menopausal pregnant," he said. "The aim is to help a growing number of women who find ... that they're ready in life to start a family, but biologically they might have missed the mark slightly."

"Mice mimic our biological processes so it is ... very promising," Dr Listijono said. "One day we could potentially use a simple pill to improve oocyte [egg] quality and with that, fertility."

The research involves a family of proteins called sirtuins​. One sirtuin regulates a particular protein, the levels of which drop in eggs from older women. Ageing mice and mice given chemotherapy were fed the precursor to a chemical which activates sirtuin naturally. 

"When we do that in aged mice we find we can improve their fertility,"  Professor Homer, a fertility expert, said. "And some of the preliminary findings suggest that we can actually reverse what is quite severe infertility."

The treatment also seemed to protect eggs during chemotherapy, which can leave cancer survivors unable to have children.

"We know that chemotherapy leads to infertility through irreversible damage to the oocyte," Dr Listijono said. The preliminary research suggests an ability to  "reverse the infertility caused by chemotherapy", he said.

Subject to funding, the researchers hope to move on to clinical trials "within a few years", Professor Homer said.