The Use of HET-CAM Test in Detecting the Ocular Irritation

Agrochemicals must undergo numerous toxicological tests before registration. One of these experiments is the examination of eye irritation potential. To get knowledge about eye irritation, recently only the in vivo Draize-test is accepted, which is one of the most criticized methods because of the injuries inflicted on the test animals. Several in vitro methods have been used to investigate the toxicity of potential eye irritants with a view to replacing in vivo eye irritation testing. In the HET-CAM test chemicals are placed in direct contact with chorioallantoic membrane of the hen's egg. The occurrence of vascular injury or coagulation in response to a compound is the basis for employing this technique as an indication of the likelihood that a chemical would damage mucous membranes (especially the eye) in vivo. In our studies comparative screening was performed with a set of agrochemicals to establish paralell data on in vitro (HET-CAM) and in vivo (Draize) results in case of 6 agrochemicals. The solutions to be tested are added to the membrane and left in contact for 5 minutes and the membrane is examined for vascular damage at set time periods. Irritancy is scored according to the severity and speed at which damage occurs providing an indication of the likely irritant effect of the compound. Our study showed good correlation between results obtained by the HET-CAM test and those of the Draize rabbit eye test most cases. The present form of the HET-CAM test can be proposed as a pre-screen method of eye irritation tests.