Corneal Epithelial Organ Culture

PURPOSE AND RATIONALE This test uses an ex vivo model of corneal organ culture, preferentially porcine, to obtain information of the possible ocular toxicity of various chemicals. This test is used as an alternative to the Draize Test to minimize or replace the use of live animal testing of ocular irritancy (Symposium, Proceeding 1996). The test allows for determination of reversibility of corneal injury following exposure to chemicals, drugs or cosmetics (Xu etal. 2004). 

The eyes are collected, prepared and maintained through specific organ culture technique prior to toxicity study. The porcine or bovine eyes may be acquired 

For acute toxicity studies, a small round 7 mm diameter filter paper is saturated with a test chemical in MEM. The filter paper is then placed onto the center of the comeal organ culture surface. After 2 minutes it is removed and the cornea is washed with PBS. Readings are then taken 0, 24,48, 72, or 96 h after exposure and are evaluated. 

CRITICAL ASSESSMENT OF THE METHOD Porcine cornea are similar to human cornea in that both have 5-7 layers of epithelial cells and a Bowman s membrane. Bovine cornea differs in that it has 10 layers of epithelial cells and no Bowman s membrane. Porcine and Bovine comeal cultures both differ in certain aspects from in vivo animal cornea. The latter has the presence of an overlying mucin layer 

Ethical concerns over the use of animals may be addressed by the use of ex vivo or in vitro cell culture models such as this. In addition comeal cell culture combined with objectively quantifiable assays for comeal epithelial barrier disruption and transactivation of stress-related genes may reduce the high variability associated to the subjectively scored Draize Test. 

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Forman DM, Pancholi S, Jarvis-Evans J et al. (1996) A simple organ culture model for assessing the effects of growth factors on corneal re-epithelialization. Exp Eye Res 62 555-564... 

Xu KP, Zhang J, Yu FSX (2004) Corneal Organ Culture Model for Assessing Epithelial Recovery After Surfactant Exposure. J of Toxicol Cut and Oc Toxicol 23(1) 29—40... 

Xu KP, Li XF, Yu FS (2000) Corneal organ culture model for assessing epithelial responses to surfactants. Toxicol Sci 58(2) 306—314... 

Ramesh GT, Manna SK, Aggarwal BB, Jadhav AL (1999) Lead activates nuclear transcription factor-kappaB, activator protein-1, and amino-terminal c-Jun kinase in pheochro-mocytoma cells. Toxicol Appl Pharmacol 155 280-286 Xu KP, Li XF, Yu FS (2000) Corneal organ culture model for assessing epithelial responses to surfactants. Toxicol Sci 58(2) 306-314... 

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