The rats developed a blue tinge after treatment
A dye similar to that used in sweets may potentially minimise the severity of spinal cord injuries.
A cascade of molecular changes triggered in the hours following an initial injury can cause further severe damage to the spinal cord.
But US researchers found this can be halted by using a dye known as Brilliant Blue G (BBG).
However, rats given the treatment in the Proceedings of the National Academy of Sciences study turned blue.
The researchers, from the University of Rochester, hope their work might eventually provide a way to minimise the risk of paralysis following a traumatic injury to the spine.
But they stress that much work will be required to come up with a practical treatment.
And the treatment would only work if it was administered in the hours immediately after an injury.
However, researcher Professor Steven Goldman said: "We have no effective treatment now for patients who have an acute spinal cord injury.
"Our hope is that this work will lead to a practical, safe agent that can be given to patients shortly after injury, for the purpose of decreasing the secondary damage that we have to otherwise expect."
The Rochester team had previously shown that ATP, a vital energy source that keeps the body's cells alive, quickly pours into the area surrounding a spinal cord injury after it occurs.
Spinal injuries can be very difficult to treat
Unfortunately, the release of ATP at hundreds of times the normal level kills off healthy, uninjured motor neurone cells by flooding them with a deluge of molecular signals, making the initial injury worse.
The researchers went on to inject rats with damaged spinal cords with oxidized ATP, a compound known to block ATP's effects.
The animals were able to recover much of their lost limb function, to the point of being able to walk again.
However, oxidized ATP carries a risk of dangerous side effects.
It also had to be injected directly into the site of a wound to achieve results - not a practical option for treating spinal injury patients.
The beauty of BBG - the chemical equivalent of blue food dye No1 - is that it could potentially be given as a standard injection, away from the wound itself.
In tests on rats, an injection of BBG produced very similar effects to those achieved by oxidized ATP.
There was just one curious side effect - the animals temporarily developed a blue tinge to their skin.
Dr Mark Bacon, head of research at the charity Spinal Research, said: "There may be little we can do to stop the initial traumatic injury but we can certainly look to stop the insidious secondary damage that occurs in the spinal cord in the hours and days immediately afterwards.
"What we appear to have here is a promising lead in this quest for so-called neuroprotective treatments.
"The fact that it is a known, approved food colourant would, on the face of it, appear to make this a compelling starting point.
"However, the levels ingested in food stuffs don't make us go blue, as is the case in the group's experimental studies on rats, suggesting the therapeutic dose needed to protect the spinal cord from ATP toxicity is far, far higher than that experienced in daily life.
"What is safe at one dose may not be safe at higher doses - many drugs have failed because they reach a toxicity threshold before they ever reach therapeutic levels."