Researchers at Kyoto University have reported that targeted messenger RNA (mRNA) delivery can restore sperm production and fertility in genetically infertile male mice. The study, published in Stem Cell Reports, showed that a temporary mRNA treatment led to the birth of healthy offspring from previously infertile animals.
According to the World Health Organization, infertility affects about 10% of couples globally, with male factors responsible for roughly half of these cases. Many instances of male infertility are due to genetic defects that disrupt sperm development.
The research team, led by Takashi Shinohara, injected mRNA into the testes of mice. This molecule carries the blueprint for specific genes but does not cause permanent changes to the cells’ DNA. The researchers verified that their method delivered mRNA directly to sperm-producing cells and supporting Sertoli cells in the testis.
The experiment focused on male mice with a genetic defect in Sertoli cells that prevents sperm production—a condition also seen in some human infertility cases. After injection, the delivered mRNA remained active for two days and was enough to restart spermatogenesis in these mice.
Sperm collected from treated animals were able to fertilize mouse eggs through in vitro fertilization, resulting in healthy offspring.
"This work demonstrates that mRNA delivery can rescue a specific genetic defect underlying male infertility in mice," said the authors. "Additional studies in animal models will be required to evaluate safety and efficacy before considering potential clinical applications in human patients."
