title: A superoxide-producing system in the conjunctival mucus thread.
abstract: In normal sterile eyes, the conjunctival mucus thread is capable of reducing the vital stain iodonitrotetrazolium (INT). The greatly increased amount of INT reduction in bacterial conjunctivitis has been used as a clinical test for this disorder. We find that native superoxide dismutase, but not the heat inactivated enzyme, inhibits INT reduction by the conjunctival mucus thread in vitro as well as in vivo in sterile rabbit eyes. Furthermore, 3,4-dihydroxybenzoic acid (DHBA), a scavenger of superoxide radical (O2-), inhibits INT reduction by the mucus thread. We conclude that INT reduction by the mucus thread is due to a superoxide radical-producing system similar to that apparently responsible for the tetrazolium-reducing properties of granulocytes and other phagocytes. This oxygen radical-producing system may serve as a defense against infection and possibly as a mediator of the conjunctival inflammatory response.
mesh_terms: D000818:Animals; D003228:Conjunctiva / Q000187:drug effects / Q000378:metabolism*; D062385:Hydroxybenzoates / Q000494:pharmacology; D008297:Male; D009093:Mucus / Q000187:drug effects / Q000378:metabolism*; D010100:Oxygen; D011817:Rabbits; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides; D013778:Tetrazolium Salts / Q000378:metabolism
chemical_list: D062385:Hydroxybenzoates; D013778:Tetrazolium Salts; D013481:Superoxides; D013482:Superoxide Dismutase; D010100:Oxygen