Endotoxin-induced uveitis in the rat: a hypothesis for preferential involvement of the anterior uvea.

Endotoxin-induced Uveitis (EIU) was produced in Lewis rats by footpad injection of Salmonella endotoxin. Protein and cells were measured both in the aqueous humor and in the cerebrospinal fluid (CSF) in order to examine if the inflammation was strictly limited to the anterior uvea. EIU was also induced in Fischer and Brown Norway rats and the inflammation was compared among the three strains. Although the function and structure of the choroid plexus is very similar to the ciliary body, no signs of inflammation were seen in the choroid plexus and the CSF. Among the 3 tested strains of rats, EIU was maximal in Lewis rats, less severe in Fischer rats and least pronounced in Brown Norway rats. It is thought that because of its specific microvascular structure, the ciliary body is specially prone to endotoxin induced inflammation. The amount of inflammation however depends on the genetic background of the animal.