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Lab mice hurt to assess face expressions

http://news.smh.com.au/breaking-news-world/lab-mice-hurt-to-assess-face-expressions-20100509-ulv7.html

Lab mice hurt to assess face expressions
JOHN VON RADOWITZ
May 9, 2010 - 9:39PM

PAA

Laboratory mice display human-like facial expressions when they are in pain, scientists learned.

Researchers drew up a "mouse grimace scale" (MGS) for measuring rodent pain based on five distinct "pain faces".

They hope the findings, the first scientific evidence of facial expression of pain in a non-human species, will assist research and help prevent unnecessary suffering in lab mice.

Humans show pain through facial expressions which have been coded and used to assess the pain of patients who cannot communicate their suffering in other ways, such as babies.

A team of Canadian and Dutch scientists set out to see if a similar approach could be applied to laboratory mice, millions of which are used in scientific experiments.

However to carry out the study, they had to inflict pain on the mice.

This was done by injecting stomachs and paws with pain-inducing substances, including acetic acid, mustard oil, and capsaicin, the "hot" ingredient in chillies.

Animals were also injected with a chemical that triggers bladder cystitis, and made to suffer nerve damage.

The "pain faces" were identified by comparing video images of non-suffering mice with those in pain.

They were listed as: orbital tightening (eye squeezing), nose bulge - a rounded extension of skin on the bridge of the nose - bulging cheeks, ears drawn apart and back, and whiskers held against the face or standing on end.

Three expressions - orbital tightening, nose bulge and cheek bulge - were said to be "identical to those observed in humans".

The scientists, led by Dr Jeffrey Mogil from McGill University in Montreal, outlined their findings in the journal Nature Methods.

They wrote: "Despite evidence that non-human mammals including rats exhibit facial expressions of other emotional states, there has been no study of facial expressions of pain in any non-human species.

"Considering the pain field's heavy and continuing dependence on rodent models and the paucity of usable measures of spontaneous (as opposed to experimenter-evoked) pain in animals, the ability to reliably and accurately detect pain, in real time, using facial expression, might offer a unique and powerful scientific tool in addition to having obvious benefits for veterinary medicine."

The accuracy of the "mouse grimace scale" was tested by inviting a group of student volunteers to rate unlabelled photos of mice for pain severity.

Scores of zero (no pain), one (moderately visible pain) or two (severe pain) were assigned for each photo. The volunteers also gave an overall verdict on whether each mouse was in pain or not.

On average, the judgments of the students were 72 per cent correct.

Pain stimuli of "moderate duration" lasting between 10 minutes and four hours were most likely to prompt a "pain face", said the scientists.

Mutant mice genetically engineered to suffer migraine were found to display "pain faces" all the time.

All the experiments were approved by the McGill University animal care and use committee, the researchers pointed out.

However, the study outraged anti-vivisectionists. Dr Ned Buyukmihci, veterinary adviser at the British Union for the Abolition of Vivisection (BUAV), said: "The BUAV is shocked by the nature of these experiments. These mice were subjected to atrociously painful situations without the benefit of any pain relief.

"Some were mutilated surgically, although while under anaesthesia, and then were allowed to recover without any further pain relief.

"People should be clear that this study was not in any way intended to improve or positively impact on the welfare of mice (or any other animal). It was not intended in anyway to mitigate painful situations for mice used in research, rather just to find a new way of determining if a mouse is showing signs of pain.

"The findings are intended to be used in studies which purposefully cause pain in mice, thus institutionalising those kinds of experiments."
© 2010 AAP


Researchers drew up a ''mouse grimace scale'' (MGS) for measuring rodent pain based on five distinct ''pain faces''.

They hope the findings, the first scientific evidence of facial expression of pain in a non-human species, will assist research and help prevent unnecessary suffering in lab mice.

Humans show pain through facial expressions which have been coded and used to assess the pain of patients who cannot communicate their suffering in other ways, such as babies.

A team of Canadian and Dutch scientists set out to see if a similar approach could be applied to laboratory mice, millions of which are used in scientific experiments.

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full story:
http://www.telegraph.co.uk/health/healthnews/7699915/Pain-for-laboratory-mice-revealed-in-human-facial-expressions.html


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