The chick chorioallantoic membrane imaging method as a platform to evaluate vasoactivity and assess irritancy of compounds

Abstract

Objective To determine if the chick chorioallantoic membrane (CAM) is a potential alternative that is capable of screening test substances for vasoactivity in terms of vessel diameter changes. The CAM was also evaluated as a tool for irritancy screening. Methods Visual assessment of the CAM for irritancy after the application of the test substance or solvent to its surface was made. An imaging based-in-vivo CAM model was developed by imaging CAM blood vessels in a pre-defined area using a semi-automatic image processing and analysis technique to measure blood vessel diameters. Solvents and drugs such as 70% v/v ethanol, normal saline, 5% w/v glucose monohydrate, glycerin, glucagon, N-methylpyrrolidone, nicotine, glyceryl trinitrate, glucagon, propranolol and caffeine were tested on the CAM. Key findings Propranolol, nicotine and glycerin were irritants on CAM. Changes in the diameters of fine blood vessels were accurately measured by high resolution image analysis. Vasoconstriction was seen with 70% v/v ethanol while vasodilation was displayed with glucagon and caffeine. The results reflected expected trends with evidence of feedback mechanisms ensuring homeostasis. Conclusion The CAM model can be applied to assess pharmaceutical and cosmetic formulations in early development work to gain useful insights to potential irritancy and biological effects of components and formulations. © 2012 Royal Pharmaceutical Society.