Activating the body's own repair system

Doses of a painkiller were able to save the sight of mice with retinal degeneration (RD) – and a similar treatment may be able to do the same in humans.

Researchers at Augusta University in the US believe they may have found a clinical way to treat patients with inherited RD.

In research published in the journal PNAS, the researchers successfully protected the photoreceptor functions of mice that lose their rods and cones within the first few weeks after birth, leaving them blind.

The team believed a cellular protection protein, known as the sigma 1 receptor (Sig1R), could prevent this degeneration.

The protein was already known to play a “multi-faceted” role in preventing cells from dying, the team noted in the paper.

Over several weeks the researchers gave the mice a molecule that activated this protein receptor. Tests confirmed the cones of the mice given this treatment continued to function.

The protein-activating molecule, pentazocine, is a non-addictive opioid already used to treat people’s moderate to severe pain. Using tests on mice without the normal Sig1R protein, the scientists concluded that pentazocine’s activation of Sig1R is the way in which the drug helps to protect the retina.

The scientists explained that their findings “may have far-reaching therapeutic implications for retinal neurodegenerative diseases.”

However, more research was needed, particularly to see if the neuroprotective effects lasted for longer than the few weeks of the initial trial. Studies looking at exactly how the process protected the photoreceptors of the mice are also necessary, the paper concluded.