Every year millions of stray dogs and cats are euthanized because of overpopulation. Those numbers could be greatly reduced with spaying and neutering, but costs can be prohibitive for sheltered and unwanted animals. Leanne Stalker, a postdoc working in the lab of Prof. Jonathan LaMarre in Biomedical Sciences, is attempting to develop a nonsurgical method to sterilize pets by understanding fertility at the cellular level.

A $260,000 Michelson Grant from the Found Animals Foundation is funding the research.

The project focuses on inhibiting the activity of a group of small RNAs (ribonucleic acids) that act like molecular switches to control the production of eggs and sperm.

“The types of RNAs we work on are part of the pathways that control how cells grow and mature in the ovary and testes of dogs and cats,” says Stalker. Ultimately, they hope to develop a way to turn off the switches that regulate fertility without causing adverse health effects in the animal.

“We want to be very specific in what we go after,” says LaMarre. “We want those genes that control fertility — the production of sperm and the production of eggs.”

The researchers are trying to develop a method of injecting animals with inhibitors that would permanently shut down the production of these reproductive cells by binding to the RNAs responsible for fertility.

As pet owners become more health conscious about their animals, there’s growing interest in sterilization options that have minimal side effects, says Stalker.

“Every time you go into surgery, there is some small risk,” she says. “That risk is higher in stray and shelter animals with uncertain health backgrounds.” It’s also riskier in places where access to veterinary care isn’t widely available. “Being able to decrease the risk and still achieve the end goal of a non-fertile pet ready for adoption is highly advantageous to overall pet welfare.” Reducing the costs associated with these procedures in at-risk populations would also be a significant step forward.

Removing an animal’s reproductive organs also removes the hormones those organs produce for some other physiological functions. Although this has some positive effects, approaches that decrease but don’t completely eliminate hormonal effects may be beneficial. “We want to make sure we’re doing good without doing harm,” says Stalker.

In addition to benefiting animals, population control for stray dogs and cats would also help limit the spread of diseases they can transmit to humans such as rabies. A simple, permanent sterilization procedure would be particularly effective on stray animals because they wouldn’t need to be recaptured for a second dose.

Stalker, LaMarre and their research team are not performing any experiments on animals in the current project. Instead, the scientific basis for their approach is being developed in tissues from animals spayed or neutered at local Humane Societies. “It’s a project that does not involve an active animal testing component,” says Stalker. “We’re lucky because the tissues we need to work on are removed and available on a daily basis.”

The research is also providing a better understanding of fertility and reproduction in many different species.

“While we’re trying to come up with a golden bullet for sterilization, this project is providing a lot of new knowledge about reproductive systems in a wide range of animals,” says Stalker. “That has an impact on animal and human health.