The Expression Of INOS And Arginine-metabolic Enzyme In Endotoxin-induced Uveitis

Objective: To observe the expression of inducible nitric oxide synthase (iNOS) andarginine relative metabolic enzyme in the ocular tissues of Wistar rats with endotoxininduced uveitis(EIU).Methods: Wistar rats were randomly divided into 7 groups.Themodel of EIU was induced in rats in experimental group by injecting with LPS 200μlinto the hind feet pads,while the rats in control group were injected 200μl SodiumChloride.Rats were executed 0,3,6,12,24,and 48 hours respectively after injectingwith LPS.The NO concentration and the protein concentration in aqueous humor wasexamined.The expression of iNOS, argininosuccinate synthetase(AS) andargininosuccinate lyase(AL) in the ocular tissues were detected by semi-quantitativereverse transcription-polymerase chain reaction (RT-PCR)andimmunohistochemistry.Results: RT-PCR shows that expression of iNOS mRNAincreased markedly 3 hours after injection, reached peak at 12 hours,and then droppedgradually.AS mRNA follows a very similar time course with iNOS mRNA, increasedmaximumly at 12hours(by about 3.5-fold).The expression of AL mRNA just changedlittle.By immtmohistochemistry iNOS can be observed expressing in the epithelialcells of iris and ciliary body,exudated inflammatory cells in vitreous and inner layersof the retina. The concentration of protein and the contents of NO in aqueous humorbecame high at 6 hours and reached the peak at 24 hours and then droppedgradually.Conclusions: During the development of EIU,iNOS was induced and a lotof NO was synthesized.Cirtrulline-NO cycle was the major sourse of arginine whichis the substrate of NO synthesis.