Scientists have healed a rat's severed spinal cord.

Stem cells from a human’s mouth were used in the process.

Researchers hope to test the pioneering surgery on humans in the future.

Seeing a rat scurry by would send many people running away screaming, but researchers at Israel's Technion institute of technology were joyful when they saw one particular rodent walking.

The rat, once paralysed with a completely severed spinal cord, had weeks earlier undergone pioneering surgery, as part of research headed by Technion and Tel Aviv University.

Professor Shulamit Levenberg, Dean of the Biomedical Engineering Faculty at the Technion, told Reuters: "In this project we managed to induce spinal cord regeneration following complete injury to the spinal cord, and this was to the extent where the animal that was totally paralysed started to walk again and also regained sensory perception."

Levenberg's team, together with Professor Daniel Offen's researchers from Tel Aviv University, used stem cells from an adult human's mouth and placed them on a sponge-like, biodegradable scaffold, which was transplanted into the site of the rat's spinal cord injury. This effectively created a pathway circumventing the injured area so that instructions from the brain could reach the rest of the body.

"It was amazing to see the animals starting to walk after 2-3 weeks. They started to walk almost as normal and we were very excited to see this," she added.

The research was launched following a request from Israel's Foundation for Spinal Cord Injury in an attempt to tackle the common, yet incurable bodily damage.

In the U.S. alone, some 17,000 patients suffer spinal cord injury each year. Despite rehabilitation protocols and other neuronal transplants, a full recovery of a severed spinal cord has yet to be accomplished in humans.

Levenberg hopes her research will change that, but warns that there is still a long way to go before it reaches the stage of clinical trials in humans.

"These are very early studies and we still don't know how it will work in humans," she added.

"This is the big challenge: to treat spinal cord after full transection because we know that spinal cord can not recover by itself," added Professor Offen, who heads Tel Aviv University's Neuroscience Lab.

"What we tried to do was to take human stem cells, did some modification and differentiation, and transplanted it with some bio material, some polymer, that was put inside the spinal cord," he explained.

About 40 percent of the animals that received the treatment regained movement and sensory perception, said Levenberg.

Some regeneration of the spinal cord was seen in the rest of the animals, but not to the extent of full recovery, she added.

The rats were treated shortly after the injury, which allowed the treatment to be effective, Professor Offen estimated. In older injuries, where the part of the spinal cord that was cut off by the injury has had time to atrophy, this solution may not show such positive results.

In the future, he hopes this treatment could be part of every operating room's basic equipment, allowing doctors to treat spinal injuries as soon as possible.

"Our vision is that in the surgery room there will be frozen cells that once a patient come after full transection of the spinal cord, these cells could be transplanted into the lesion site."

In an experiment publicised in 2012, paralysed rats were helped to walk involuntarily over obstacles by electrically stimulating the severed part of their spinal cord, in research carried out at Switzerland's EPFL. Professor Gregoire Courtine's team announced similar results with monkeys last year.