AIM:To investigate the expression and function of TNF- related apoptosis-inducing ligand(TRAIL)apoptosis system on infiltrated cells in Sprague-Dawley(SD)rats with endotoxin-induced uveitis(EIU), and to study the role of TRAIL on apoptosis.

METHODS: EIU model was established by injecting a dose of 1mg/kg endotoxin(LPS)into the footpads of SD rats. At different time points(6, 12, 18, 24, 48 hours)after endotoxin injection, clinical symptoms were observed with ophthalmoscope. The cells in the aqueous humor one eye in each rat were counted. Eyes were enucleated for histological examination at different time points. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay(TUNEL)method was used to assess the infiltrated cells apoptosis. The expression of TRAIL was determined by sreptavidin-biotin complex(SABC)immune histochemistry. The positive stain section was analyzed by computer-based image analysis system.

RESULTS: Intraocular inflammation appeared 6 hours after LPS injection, peaked at 18-24 hours, and obviously weakened at 48 hours. The cells of aqueous humor were gradually increased peaked at 24 hours. TUNEL stain indicated: a number of apoptotic infiltrated cells could be seen at the time of 6 hours to 24 hours after endotoxin injection. TRAIL was constitutively expressed on the rat iris weakly. TRAIL was expressed on the infiltrated cells. The intensity was weak in the 6 hours, 12 hours, at a peak in the 18 to 24 hours.

CONCLUSION: Uveitis was induced in the rat eyes with injecting 1mg/kg endotoxin. The short duration of EIU may be associated with apoptosis of infiltrated cells in inflammation. The TRAIL system may be associated with the infiltrated cells apoptosis in EIU.