Chickens could save rabbits from painful tests

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Chickens could save rabbits from painful tests

http://www.newscientist.com/nsplus/insight/animalexperiments/animalnews5.htm

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Thousands of rabbits could be saved from distressing experiments if dead

chickens were used in their place, a conference in Utrecht was told last

week.

 

Rabbits are widely used to establish whether chemicals, such as those used

in cosmetics, are hazardous to humans. In the Draize test, prescribed by the

European Commission, chemicals are dripped into rabbits' eyes. The redness

of their eyelids and opacity of their corneas are then taken as a measure of

the damage the chemicals can cause. But Menk Prinsen of the Dutch research

organisation TNO in Zeist says that equally accurate results can be obtained

using the eyes of butchered chickens from slaughterhouses.

 

Prinsen says he can measure the potency of a chemical from its effect on the

thickness of a chicken's cornea. The cornea remains active for several hours

after death, so the results are as accurate as those from the eyes of living

animals, he says.

 

An irritating substance will leave holes in the thin surface membrane of the

cornea. Water applied to the surface can then reach the spongy stroma inside

the cornea, causing it to swell. Intact, a chicken's cornea is slightly

thicker than half a millimetre; when damaged, it can swell by up to 60 per

cent.

 

" His method has great potential, " says Michael Balls, head of the European

Centre for Validation of Alternative Methods in Ispra, Italy. " But there's a

great deal of difficulty with replacing the rabbit eye test. "

 

Britain's Home Office and the European Commission tested Prinsen's method

two years ago, along with other alternatives. These included tests with

cows' eyes and blood vessels from chicken embryos. But none could reliably

reproduce the results of the rabbit eye test. The reason, says Balls, is

that " the data from rabbit tests themselves are so variable they can't be

reproduced " .

 

Prinsen argues that this is because the redness, swelling and opacity of rab

bits' eyes are estimated subjectively, and what one researcher calls " light "

redness, another calls " heavy " . " Since no test can duplicate this, European

regulators and industry stick to the old ways. "

 

Prinsen thinks his test, or something similar, could at least be used to

separate out the totally innocent or very dangerous chemicals from more

borderline cases. This would cut the number of live rabbits used in tests.

 

Balls understands Prinsen's frustration: " There's conservatism with the

regulators as well as industry. But there's willingness in both camps too. "

The European Commission plans to ban the Draize test in the cosmetics

industry from 1998 if there is an alternative available that satisfies

everyone.

 

Herbert Blankesteijn, Utrecht