Bio-inspired hydrogel stimulates nerve regrowth and heals spinal cord injuries

Scientists have developed a method for healing spinal cord injuries in animals that shows promise, including improving motor function during recovery.

They developed a novel hydrogel composed of hyaluronic acid-graft-dopamine (HADA) and a designer peptide HGF-(RADA)4-DGDRGDS (HRR) to improve tissue integration after spinal cord injury (SCI).

In an official statement released by the American Association for the Advancement of Science, the researchers said the new hydrogel stimulates nerve regrowth after spinal cord injury in animals.

Stimulating nerve regrowth after spinal cord injury

“This strategy holds promise for further applications in the repair of other central nervous system injuries and diseases,” the authors said.

“The gel transforms dense scar tissue into a welcoming environment where tissue repair-promoting cells can infiltrate and support nerve healing,” the statement added.

When the spinal cord is injured, called traumatic spinal cord injury (SCI), it typically produces dense scar tissue called fibrous scarring. This makes it difficult for nerve cells to grow back.

However, the researchers noted that using specific biomaterials could help create a better environment for these nerves to repair and regrow in the scarred area.

Encouraging axonal repair of spinal cord scars

Scientists said that this dense tissue is not a suitable environment for the regeneration of nerve axons. Implanting selected biomaterials could be a way to promote axonal repair of spinal cord scars.

The study showed that hyaluronic acid-graft-dopamine (HADA) and designer peptide (HRR) hydrogel were enhanced by curcumin and neurotrophin-3 (NT-3).

Since NT-3 is a nerve growth promoting element, it greatly improved motor, sensory and bladder functions in rats and motor functions in canines by promoting nerve regrowth.

Additionally, the hydrogel transformed the scar tissue into an environment conducive to axonal growth.

The study authors said the HADA/HRR hydrogel manipulated PDGFRβ+ cell infiltration in a parallel pattern, transforming dense scars into an aligned fibrous substrate that guided axonal regrowth.

“Additional incorporation of NT-3 and curcumin promoted axonal regrowth and survival of interneurons at lesion boundaries, which served as relays to establish heterogeneous axonal connections in a target-specific manner.”

Furthermore, in vitro analyses illustrated the ability of the hydrogel to promote fibroblast infiltration, while in vivo tests on rat models with complete spinal cord section and canines with hemisected lesions showed significant functional improvements.

According to the statement, rat models that underwent complete spinal cord transection and received hydrogel treatment showed improved bladder, sensory and motor activity, including recovery of locomotion.

“Canids with hemisected lesions showed similar improvements in motor function,” the authors added.

This strategy holds promise for further applications in the repair of other central nervous system injuries and diseases. The authors noted that such biomaterials may inspire biological activities beneficial for spinal cord injury repair.

The study was published earlier today (July 3, 2024) in the journal – Scientific progress.