ObjectiveTo investigate the cytotoxicity of triamcinolone acetonide (TA) on cultured human retinal pigment epithelial (RPE) cells.MethodsEffect of TA with different concentraion (0.4, 02, 01, 0.05, and 0.025 mg/ml) on the proliferation of RPE cells was detected by methyl thiazolyl tetrazolial (MTT) assay; The changes of cellular cycle treated by TA with the drug concentration of IC50 for 72 hours were measured by flow cytometry (FCM) ananlysis, and the morphological and ultrastructural changes of the cells were observed by phasecontrast microscopy and transmission electron microscopy.ResultsWith the concentration of 0.4-0.025 mg/ml, TA inhibited the growth of RPE cells obviously in a dose-dependent manner compared with the control (P＜0.05), and the cells in S phase treated with TA decreased 10.6% compared with the control (P＜0.05). Under the light microscope, sparse cells with irregular configuration and many prominences and cellular vacuoles in TA group can be seen. The results of transmission electron microscopy showed asymmetrically distributed cellular chromatin was, cavitated cytoplasm, and even some necrotic cells.ConclusionTA can inhibite the S-phase karyomitosis of RPE and inhibite the cellular proliferation; and destroye the cellular structure and lead to the necrosis, which indicates the cytotoxicity of TA on RPE.(Chin J Ocul Fundus Dis, 2005,21:233-236)
The internal limiting membrane (ILM), composed of collagen fibers, glycosaminoglycans, laminin and fibronectin, is the basement membrane of the retinal Müller glia cells and serves as an interface between the vitreous and retina. The ILM is the structural interface between the vitreous and retina. ILM removal ensures separation of the posterior hyaloid from the macular surface, which can relieve macular traction and prevent postoperative epiretinal membrane formation. Thus, vitrectomy with ILM peeling has become an increasingly utilized and vital component in surgical intervention for various vitreoretinal disorders. However, many recent studies showed that ILM peeling is a procedure that can cause immediate traumatic effects and progressive modification on the underlying inner retinal layers.There were some surgical strategy (fovea-sparing ILM peeling or inverted internal limiting membrane flap technique, or Abrasion Technique). But some controversies exist, such as when ILM peeling is necessary, which adjuvant to use to perform the procedure, and what is the best technique to peel the ILM. A full assessment ILM structure and function and related factors of surgery is helpful to predict the anatomical and functional prognosis.