The inflammatory role of endotoxin in rabbit gram-negative bacterial endophthalmitis

The authors used the limulus lysate assays to measure the amount of gram-negative endotoxin produced in two rabbits with experimentally induced gram-negative (Escherichia coli) endophthalmitis. A similar amount of purified enodotoxin was injected into the eyes of 14 rabbits to determine the rate of clearance of endotoxin from the rabbit eyes. Endotoxin was found in clinically inflammatory quantities 2 weeks after injection. Results of pathologic examination showed that endotoxin incites severe inflammatory responses in the eye, affecting the ciliary body, vitreous, choroid, retina, and optic nerve. These results suggest that the limulus lysate assay may be useful for detecting early gram-negative endophthalmitis, and that in such cases, early emergency vitrectomy may be needed to remove the inflammation-inciting endotoxin and preserve useful vision.