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20/01/2015

Healthy dogs paralysed in devastating experiment

Scientists in China deliberately paralysed a group of healthy dogs before attempting to cure them with ‘breakthrough’ surgery that they claim will one day be used to treat patients with spinal cord injuries1.

In this devastating experiment2, 28 healthy female Beagle dogs were anesthetised before their backs were cut open and a section of their spinal cord was surgically removed, leaving a 5mm gap. The missing spinal cord was then replaced with a lab-grown ‘scaffold’ made of cow tendons and human proteins.

Eight of the dogs were used as ‘controls’ and did not receive any treatment, leaving them permanently paralysed from the waist down. After surgery, all of the dogs were left so severely disabled that their bladders had to be emptied manually every 12 hours for two weeks. Shockingly there was no mention of post-operative pain relief being given.

Three weeks after surgery, the dogs were forced to begin a strict daily rehabilitation program which involved being suspended off the ground to test their reflexes and having their back legs stretched and toes pinched. As well as behaviour tests, the dogs were also subjected to spinal cord measurements which involved inserting electrodes into a nerve in their backs. All of the dogs were killed 38 weeks after surgery and their spinal cords were dissected for analysis.

This so-called ‘breakthrough’ surgery, which was developed over ten years ago and previously tested in rats, enabled the paralysed dogs to stand by themselves with some being able to walk for a mere split second. A series of videos included in the online publication clearly show that despite some improvement when compared to the severely paralysed ‘control’ dogs, the animals were unable to walk properly and their condition was far from normal.

The so-called ‘clean cut’ procedure used to paralyse the dogs does not accurately reflect the reality for the majority of human spinal cord injuries, which are much more complicated and often involve fracturing, dislocation and scarring of the spine as well as damage to surrounding nerves and muscles3. Furthermore the dogs were ‘treated’ at the same time as the injury was created, which is not likely to be possible for many spinal cord injury patients and is likely to affect the success of the treatment in humans.

In a different recently published study conducted in the USA, dogs with existing spinal cord injuries were enrolled by their owners into a clinical trial of two drugs that are thought to help damaged nerves work again.4 The results clearly showed that even amongst dogs suffering from the same type of spinal cord injury, the extent of improvement was very variable  Despite extensive testing in animal experiments and human clinical trials, there is still no effective treatment for spinal cord injury. Professor Liu Yaobo, neuroscientist at Soochow University said, “Spinal cord injury is one of the biggest medical challenges we face. There may still be many years, even decades, before it can be cured1.” Sadly, the researchers are keen to move forward with testing in monkeys, which if approved, will lead to more animal suffering.

Sources:

1.       Paralysed dogs walk again in breakthrough spinal cord experiment by Chinese scientists. (2015). Southern China Morning Post: http://www.scmp.com/news/china/article/1667440/paralysed-dogs-walk-again-breakthrough-spinal-cord-experiment-chinese

2.       The linear-ordered collagen scaffold-BDNF complex significantly promotes functional recovery after completely transected spinal cord injury in canine. (2015). Biomaterials, 41: 89-96. Original article can be found here: http://www.sciencedirect.com/science/article/pii/S0142961214011910

3.       http://www.patient.co.uk/doctor/spinal-cord-injury-and-compression

4.       Potassium channel antagonists 4-aminopyridine and the t-butyl carbamate derivative of 4-aminopyridine improve hind limb function in chronically non-ambulatory dogs; a blinded, placebo-controlled trial. (2014). PLOS One, DOI: 10.1371/journal.pone.0116139

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