Scientists Unlock Key to Healing Damaged Nerves in Mice

Scientists at Mount Sinai just figured out why our bodies struggle to repair damaged nerves, and the answer could change how we treat paralysis.

The research team discovered that a protein called AHR acts like a brake pedal on nerve regeneration. When they blocked this protein in mice with spinal cord and nerve injuries, something remarkable happened: damaged nerve fibers started regrowing, and the mice recovered movement and sensation.

The findings, published in Nature, explain a puzzle that has frustrated doctors for decades. When adults suffer nerve or spinal cord damage, their neurons rarely rebuild the long fibers called axons that carry signals throughout the body. That's why these injuries often cause permanent paralysis or numbness.

Dr. Hongyan Zou, the study's lead researcher, describes AHR as a survival switch. After an injury, neurons face a choice: focus on staying alive under stress, or use their energy to rebuild damaged connections. AHR pushes neurons toward survival mode, which keeps them alive but prevents them from repairing themselves.

When the team removed AHR from neurons, the cells shifted their priorities completely. They started producing proteins needed for growth and activated pathways associated with tissue repair. The injured mice showed measurably better recovery of both movement and sensation.

The discovery gets even more interesting. AHR was originally identified because it detects environmental toxins and pollutants. Scientists had no idea it also controlled nerve repair inside the body.

Why This Inspires

This research offers genuine hope for millions living with nerve damage and spinal cord injuries. Several drugs that block AHR already exist and are being tested for other conditions, which means researchers won't need to start from scratch.

The Mount Sinai team is now planning studies to test AHR-blocking drugs and gene therapy approaches that target the protein specifically in neurons. They want to see if these strategies work for spinal cord injuries, stroke, and other neurological conditions.

The work remains early stage, and years of additional research lie ahead before human trials could begin. Scientists still need to determine the right timing, dosage, and how blocking AHR affects other cells involved in healing.

But for the first time, researchers understand a fundamental reason why nerve regeneration fails in adults. That knowledge opens a door that was previously locked, turning what seemed like a permanent limitation into a problem that might actually have a solution.