TY - JOUR
T1 - Intravitreal triamcinolone acetonide induced changes in the anterior segment in a pig model of branch retinal vein occlusion
AU - Vijayasekaran, Sarojini
AU - Mcallister, Ian
AU - Morgan, William
AU - Mendis, K.R.
AU - Mcmenamin, Paul
AU - Cringle, Stephen
AU - Yu, Dao-Yi
PY - 2011/2
Y1 - 2011/2
N2 - BACKGROUND: Triamcinolone acetonide (TA) has applications for the treatment of a large range of intraocular vascular diseases. The present study in pigs was performed to investigate histopathological and histochemical changes in the levels of myocilin deposition in the anterior segment in a model of branch retinal vein occlusion (BRVO) after vitreal administration of TA.METHODS: After ophthalmoscopic examination, intraocular pressure (IOP) measurement and fundus photography, a BRVO was created photothrombotically in each eye of six pigs, using argon green photocoagulation. The left eye was then injected intravitreally with 4 mg/0.1 ml TA. After 11 weeks, the eyes were re-examined, animals sacrificed, and eyes enucleated and processed in paraffin and epoxy resin. Immunofluorescence cytochemistry on paraffin sections was performed to localise the distribution of myocilin in the anterior segment and histology by light and transmission electron microscopy on epoxy resin sections on TA-treated and untreated eyes.RESULTS: Histology revealed pathological changes in the TA-treated eye, including swollen mitochondria, layered long endoplasmic reticulum, pleomorphic nuclei, dense fibrillar extracelluar deposits and aggregates of unusual cell inclusions. Myocilin levels were significantly higher in the TA-treated eyes in the trabecular meshwork (p = 0.001), ciliary process (p = 0.011) and iris (p = 0.030) than in the untreated eyes.CONCLUSIONS: This study suggests that increased myocilin synthesis and related ultrastructural changes in the anterior segment after treatment with intravitreal TA in a porcine model of retinal oedema in BRVO may contribute to IOP elevation.
AB - BACKGROUND: Triamcinolone acetonide (TA) has applications for the treatment of a large range of intraocular vascular diseases. The present study in pigs was performed to investigate histopathological and histochemical changes in the levels of myocilin deposition in the anterior segment in a model of branch retinal vein occlusion (BRVO) after vitreal administration of TA.METHODS: After ophthalmoscopic examination, intraocular pressure (IOP) measurement and fundus photography, a BRVO was created photothrombotically in each eye of six pigs, using argon green photocoagulation. The left eye was then injected intravitreally with 4 mg/0.1 ml TA. After 11 weeks, the eyes were re-examined, animals sacrificed, and eyes enucleated and processed in paraffin and epoxy resin. Immunofluorescence cytochemistry on paraffin sections was performed to localise the distribution of myocilin in the anterior segment and histology by light and transmission electron microscopy on epoxy resin sections on TA-treated and untreated eyes.RESULTS: Histology revealed pathological changes in the TA-treated eye, including swollen mitochondria, layered long endoplasmic reticulum, pleomorphic nuclei, dense fibrillar extracelluar deposits and aggregates of unusual cell inclusions. Myocilin levels were significantly higher in the TA-treated eyes in the trabecular meshwork (p = 0.001), ciliary process (p = 0.011) and iris (p = 0.030) than in the untreated eyes.CONCLUSIONS: This study suggests that increased myocilin synthesis and related ultrastructural changes in the anterior segment after treatment with intravitreal TA in a porcine model of retinal oedema in BRVO may contribute to IOP elevation.
KW - Animals
KW - Anterior Eye Segment/drug effects
KW - Ciliary Body/drug effects
KW - Cytoskeletal Proteins/metabolism
KW - Disease Models, Animal
KW - Eye Proteins/metabolism
KW - Fluorescent Antibody Technique, Indirect
KW - Glucocorticoids/administration & dosage
KW - Glycoproteins/metabolism
KW - Intraocular Pressure/drug effects
KW - Intravitreal Injections
KW - Iris/drug effects
KW - Retinal Vein Occlusion/drug therapy
KW - Swine
KW - Trabecular Meshwork/drug effects
KW - Triamcinolone Acetonide/administration & dosage
U2 - 10.1007/s00417-010-1458-y
DO - 10.1007/s00417-010-1458-y
M3 - Article
C2 - 20652816
SN - 0721-832X
VL - 249
SP - 215
EP - 222
JO - Graefes Archive for Clinical and Experimental Ophthalmology
JF - Graefes Archive for Clinical and Experimental Ophthalmology
IS - 2
ER -