Background: Finding means for improving the effectiveness of drug therapy of ocular inflammatory disorders, especially those with comorbidities, is a challenge to ophthalmology. Purpose: To assess the efficacy of carnosine for improving the pro/antioxidative imbalance in the anterior segment of rabbit eyes with experimental anterior uveitis in the presence of ocular hypertension (OHT). Material and Methods: Thirty-three rabbits were used in the study. Group 1 (the control group) comprised 9 intact rabbits and group 2, 12 animals with OHT induced prior to experimental non-infectious uveitis. Group 3 comprised 12 animals in which carnosine 5% was administered bilaterally into the conjunctival sac twice daily for four weeks for OHT induced prior to experimental non-infectious uveitis. Non-infectious uveitis was induced by injecting albumin into the anterior chamber, and OHT was induced by a single 0.1-mL injection of carbomer 0.3% into the anterior chamber. Activities of superoxide dismutase, catalase, glutathione peroxidase, NADH-oxidase and xanthine oxidase, and levels of total proteins and malondialdehyde (MDA) and diene conjugate (DC) in uveal tissue (iris and ciliary body) and aqueous humor specimens were determined. Results: Uveal activities of NADH-oxidase and xanthine oxidase were 19.4% (р < 0.05) and 27.2% (р < 0.01), respectively, lower in eyes of rabbits treated with carnosine than in eyes of animals not treated for anterior uveitis plus OHT. Uveal activities of glutathione peroxidase, superoxide dismutase and catalase were 34. 7%, 39.6% and 28.4%, respectively, higher, and uveal MDA and DC levels were 39.3% and 33.3%, respectively, lower, in eyes of the former rabbits than of the latter rabbits. Similar changes were found in aqueous humor specimens of the experimental rabbits. Conclusion: Carnosine, when instilled locally, contributed to improvement in the pro/ antioxidative imbalance in the anterior segment of rabbit eyes with uveitis plus OHT. It is reasonable to include carnosine-based eye drops into multiagent therapy of uveitis complicated by OHT due to their antioxidative, anti-inflammatory and membranestabilizing effects.
Background:The clinical and morphological picture of diabetic microangiopathy is rather specific. Diabetic retinal ischemia can lead to irreversible damage to retinal neural elements and choroidal capillaries. Diabetic nephropathy can lead to progressive renal dysfunction and chronic renal failure. Choroidal and retinal capillaries are structurally and functionally similar to those of the intestinal mucosa and renal tissue. Purpose: To assess vascular ultrastructural changes in the choroid, retina, and renal glomerular and tubular system in a rat model of pyelonephritis in the presence of type 2 diabetes. Material and Methods: Samples were obtained from 95 Wistar rats divided into three groups: group 1 (or control group) of 30 intact animals; group 2 of 15 animals with type 2 diabetes induced by intraperitoneal streptozotocin 15.0 mg/ kg for 5 consecutive days; and group 3 of 50 animals with acute pyelonephritis in the presence of type 2 diabetes (streptozotocin 35.0 mg/kg on 2 days spaced by a week). Acute pyelonephritis was induced by Escherichia coli administration (107 CFU/kg) rectally. The ultrastructure of rat choroidal, retinal and renal glomerular-and-tubular vessels was examined with electron microscopy (PEM-100-01 electron microscope). Results: In rats with induced type 2 diabetes, the most significant ocular vascular changes and renal vascular changes were found in endothelial cells. These changes included findings of vacuolar degeneration in some epithelial cells, basal membrane thickening and focal necrosis of individual epithelial cells. Vessel lumens appeared focally narrowed or expanded, with red blood cells forming clumps or sludge in lumens. Some capillaries were obliterated. These changes obviously caused secondary changes in the surrounding structures. Common ocular changes included focal destruction in retinal pigment epithelium cells, destruction of retinal photoreceptor inner segments and choroidal stromal edema. Common renal changes included destruction of the podocytes of the glomerular capillary network and homogenization of the basal membrane. Vascular ultrastructural changes in the renal glomerular system were more marked in rats with experimental type 2 diabetes and pyelonephritis than in those with type 2 diabetes only. Conclusion:Electron microscopy micrographs demonstrated the ultrastructural changes in the retinal and uveal vascular systems which were of a similar type to those in the renal glomerular-and-tubular system in rats with experimental pyelonephritis in the presence of type 2 diabetes.
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