Eye irritation study of some pesticides on chorioallantoic membrane of the egg.

The chorioallantoic membrane of chick embryo has been used extensively for many years in various fields of biological research, including virology, bacteriology and toxicology. The chorioallantoic membrane (CAM) is a complete tissue that responds to injury with a complete inflammatory reaction, this process similar to that induced by chemicals in the conjunctival tissue of the rabbit eye. A possible model for assessing the irritation potential of a chemical or product to such a vascularised tissue is the choriallantoic membrane of the embryonated hen's egg, as this is a highly vascular, thin membrane with relatively easy access for both treatment and assessment. In recent years various in vitro methods have been developed to replace the heavily criticized Draize rabbit eye test for irritation testing. One of the most studied alternative methods is the Hen's Egg Test - Chorioallantoic membrane (HET-CAM). In our studies a comparative screening was done with a set of pesticides to establish parallel data on in vitro (HET-CAM) and in vivo (Draize) results. In most cases good correlation was found between the HET-CAM assessment and results from the Draize rabbit eye test. The actual form of the HET-CAM test is a valuable pre-screen for predicting ocular irritation potential of chemicals, and can be used to reduce the number of experimental animals. The HET-CAM test is useful as a part of a battery of tests to replace the Draize rabbit eye test.