Israeli scientists find the nervous system shields fertility from heat

Researchers from the Hebrew University of Jerusalem and Tel Aviv University reported in Current Biology, in findings publicised from 7 August 2026, that the nervous system actively helps reproductive cells survive heat stress. The work was led by Dr. Yonatan Tzur of the Hebrew University with Dr. Chee Kiang Ewe, Dr. Hanna Achache and Prof. Oded Rechavi of Tel Aviv University, together with collaborators at the Institute of Science and Technology Austria.

High temperatures are known to harm fertility in many animals, including humans and livestock, and the usual assumption has been that sperm and egg cells simply react to heat on their own. The team tested that idea in the tiny roundworm C. elegans, a workhorse of genetics research in which Rechavi's lab has long studied how small RNA molecules carry information between tissues.

They found that neurons produce small RNA molecules that travel to the germline, the cells that give rise to sperm and eggs, and help them cope with heat. When this neuronal signalling was disrupted, worms became largely infertile at high temperatures because their sperm did not develop properly. Restoring the pathway in neurons alone was enough to rescue much of their fertility. The signal also reduced heat-induced DNA damage in the reproductive cells. Strikingly, changing how the worms' oxygen-sensing neurons perceived their surroundings, without changing the environment itself, also improved reproduction under heat.

Tzur said the nervous system is not simply reacting to the environment but actively instructs reproductive cells on how to respond. Rechavi noted that, as temperatures rise, understanding the mechanisms that naturally protect reproductive cells becomes especially important. The study was carried out in worms, and whether similar brain-to-germline signalling operates in mammals has yet to be shown.