Scientists Discover Why Damaged Nerves Fail to Regrow After Injury

Scientists have uncovered a key reason why damaged nerves struggle to regrow after injury. The discovery centres on a protein called AHR, which acts like a biological brake in neurons. Instead of helping repair, it forces cells to focus on survival—until now. The aryl hydrocarbon receptor (AHR) was first known for detecting environmental toxins. But researchers found it also plays a crucial role in nerve regeneration. After an injury, AHR slows down axon growth by making neurons prioritise protecting existing proteins over building new ones.

When scientists removed or blocked AHR in experiments, neurons began mass-producing proteins needed for axon regrowth. This shift allowed damaged fibres to regrow more effectively, improving motor and sensory recovery. The team also discovered that once AHR is blocked, another factor called HIF-1α takes over. This activates metabolic genes essential for rapid tissue repair. Unlike most nerve research, which focuses on the environment around damaged cells, this study targets the neuron's internal engine. By reprogramming the cell itself, scientists aim to restore its natural ability to grow. AHR-inhibiting drugs are already in clinical trials for other conditions, which could speed up their use for nerve damage treatment. Researchers now plan to test these drugs, along with gene-therapy strategies, to boost recovery after spinal cord injuries, strokes, or other neurological diseases.

The findings suggest blocking AHR could become a powerful way to help nerves regrow after injury. Combined with physical therapy, this approach may improve recovery for patients with peripheral nerve or spinal cord damage. Clinical trials for AHR inhibitors are already underway, raising hopes for faster progress in treatment.