Study On The Retinal Toxicity Of Triamcinolone Acetonide In Silicone Oil Filled Rabbits Eyes

triamcinolone acetonide which as a white crystalline steroid has anti-edema, anti-inflammatory and anti-angiogenic effects. Contrast with soluble steroid, triamcinolone acetonide has a considerably long absorption time and the intraocular concentrations of steroids were high enough to achieve a therapeutic level, and the systemic side-effects were not pronounced. So triamcinolone acetonide has increasingly been applied in recent years for treatment of many diseases such as macular edema, age-related macular degeneration, proliferative vitreoretinopathy, uveitis, neovascular glaucoma. At the same time there were many studies on the side-effects of triamcionlone acetonide. Majority studies suggested that intravitreal 4 mg triamcinolone acetonide have no retinal toxicity, but study on the retinal toxicity of triamcinolone acetonide in silicon oil filled eyes have little. The triamcinolone acetonide crystals usually settled on the surface of inferior fundus in silicon oil filled eyes and existed for a long time. We should attend whether triamcionlone acetonide contacted with retina directly for a long time produc retinal toxicity in silicon oil filled eyes.ObjectiveTo investigate retinal toxicity of triamcinolone acetonide (TA) in silicone oil filled rabbit eyes.Materials and MethodsHealthy New Zealand rabbits, all of the eyes were performed vitrectomy and lensectomy with silicone oil tamponade. The right eyes as study group were injected 4mg/0.1ml triamcinolone acetonide before silicone oil was injected and the left eyes as control group without injection of triamcinolone acetonide. The eyes which were injured in operation or undergone retinal detachment, intraocular hypertension, endophthalmitis or other factors which could influence retinal function were excluded. There were 20 rabbits as study object. All the eyes were examinated with slit lamp, ophthalmoscopy regularly and postoperative inflammatory reaction and absorption of TA were evaluated. The eyeballs were enucleated at 12 weeks and light, electron microscopy (TEM) retinal samples were performed to observe retinal histology and evaluate toxicity.Results1. Clearance of TA: Triamcinolone acetonide was absorbed gradually and at the end of 12 weeks all of triamcinolone acetonide was absorbed.2. The effect of anti-inflammation: Triamcinolone acetonide has siginificant effect of anti-inflammation. Postoperative inflammation of study group was more slightly than that of control group. There was significant difference in postoperative inflammation between study group and control group (P<0.05).3. Histopathologic observation: The examination of light and electron microscopy showed that retina of the study group and the control group was morphologically normal. Retina had no pathological change of edema or necrosis and so on. The structure was distinct and layers arranged regularly. The ultrastructure of retinal pigment epithelium and its microvilli were normal. Bruch membrane was continuity and smooth. Membranous disc of the out segment arranged regularity and mitochondrias of the inner segment were no swollen and mitochondrias cristae were distinct. Nuclear membrane of Ganglion cell was integrity.Conclusions1. The application of 4mg triamcinolone acetonide in silicone oil filled rabbits eyes have no toxicity to retina, it's a safe treatment method.2. Intravitrial triamcinolone acetonide have significant effect of anti-inflammation and is a safe, convenient and economic anti-inflammation method.