The Center for Alternatives to Animal Testing is an academic center affiliated with the Division of Toxicological Sciences in the Department of Environmental Health Sciences of the Johns Hopkins University Bloomberg School of Public Health.

 

Johns Hopkins School of Public Health

Research Grants 2003-2004

Bovine Corneal Organ Culture: An ex vivo Model for Chemical Toxicity Tests

Keping Xu, PhD
Medical College of Georgia, Augusta, Georgia

The long-term goal has been to develop an ex vivo assay system to predict ocular irritation potential of test chemicals and consumer products. The objective of this proposal is to understand the role of growth factors released upon corneal injury in regulation of wound healing. We hypothesize that chemical or other injury induce the release of growth factors such as heparin-binding EGF-like growth factor (HB-EGF) from epithelial and hepatocyte growth factor (HGF) from stroma keratocytes and continue release of these factors is required for the recovery of corneal injury. In this study we will use porcine corneal organ culture as an experimental model (Xu KP, Li XF, Yu FX. Corneal organ culture model for assessing epithelia[ responses to surfactants. Toxicological Sciences 2000;58:306-314). The specific aims are:

  1. To determine if and at what concentrations a chemical cause the release of H13-EGF from epithelia[ cell and activation of c-MET (HGF receptor) in epithelial cells released. A variety of chemicals including detergents, alcohols, oxidants and solvents (such as propylene glycol) will be tested. We speculate that exposure of cultured corneas to a chemical causing minimal to mild ocular irritation should lead the release of H13-EGF and phosphorylation of c-MET while a chemical causing severe ocular irritancy will result in destruction of the cultured corneas.
  2. To determine if release of H13-EGF and HGF is require for the recovery using reagents specifically block HB-EGF and HGF activity.
  3. To determine whether exogenous HB-EGF and HGF prevent chemical from inducing cell death and enhance corneal recovery after chemical exposure. Our previous studies have proved the usefulness of corneal organ culture in assessing chemical toxicity.

The proposed study will provide a better understanding of molecular bases for corneal response to and recovery from chemical injury and several measurable ex vivo parameters much needed for developing an ex vivo model for evaluating the ocular initancy potential of chemicals and consumer products.