latanoprost and Reperfusion-Injury

Purpose. To determine the neuroprotective properties of a latanoprost acid derivative (ACS67) that donates the gas hydrogen sulfide (H(2)S). Methods. Ischemia to the rat retina was induced by elevation of intraocular pressure. Electroretinograms (ERGs) were recorded and the retinas analyzed 2 days later by immunohistochemistry, Western blot analysis, and RT-PCR. Hydrogen peroxide (H(2)O(2)) was used to impose an insult on RGC-5 cells in culture. The nature of the insult to cultures was quantified by the resazurin-reduction assay procedure, staining for reactive oxygen species (ROS) and for apoptosis. ACS67, its sulfurated moiety (ACS1), and latanoprost were tested for both their toxicity and ability to blunt the negative effect of H(2)O(2) on RGC-5 cells. In addition, an assay was used to see whether any of the substances influenced glutathione (GSH) levels in RGC-5 cells. Results. Partial damage to the retina in situ after ischemia was characterized by an alteration of the ERG, a reduction in the retinal localization of specific antigens and a reduction and elevation of defined retinal proteins and mRNAs. Optic nerve axonal proteins were also drastically reduced by ischemia. Most of these changes were significantly blunted by an intravitreal injection of ACS67 directly after ischemia. ACS67, ACS1, and the antioxidant epigallocatechin gallate (EGCG) all stimulated GSH levels and significantly attenuated H(2)O(2)-induced toxicity to RGC-5 cells, whereas latanoprost did not. Conclusions. ACS67 acts as an H(2)S donor through its donating moiety ACS1 and as a consequence is able to act as a neuroprotectant.

Topics: Animals; Blotting, Western; Caspases; Cells, Cultured; Disease Models, Animal; Electrophoresis, Polyacrylamide Gel; Electroretinography; Fluorescent Antibody Technique, Indirect; Glial Fibrillary Acidic Protein; Glutathione; Hydrogen Peroxide; Hydrogen Sulfide; Latanoprost; Nitric Oxide Synthase Type I; Oxidative Stress; Prostaglandins F, Synthetic; Rats; Reperfusion Injury; Retinal Diseases; Retinal Ganglion Cells; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Thioctic Acid; Thy-1 Antigens

This study was planned to investigate the neuroprotective potentials of three commercially available prostaglandin analogues (PGA), in the ischemia and reperfusion model (I/R). Thirty New Zealand rabbits were divided into 5 groups and except for the control group (non-ischemic, non-treated), 0.9% NaCl, bimatoprost, latanoprost, or travoprost were applied to both eyes of animals of the respective groups for 1 week. At the end of treatment, ischemia was induced in both eyes of the 4 treatment groups by anterior chamber irrigation of the animals for 60 min. Following 24 h reperfusion, the animals were sacrificed. Enucleated eyes and retinal tissues were investigated by light microscopy, electron microscopy, immunohistochemicstry for retinal histopathology, intracellular and apoptotic cells and by retinal morphometry. Vitreous samples were biochemically investigated for probable role of reactive oxygen species, by measuring xanthine oxidase (XO) activity. Analysis of morphometric measurements and vitreous XO activity revealed significant differences between the PGA-treated groups and the NaCl-treated group (P<0.05). Similarly, apoptotic cell counts in different retinal layers showed that PGA-treated groups had fewer apoptotic cells in all retinal layers than the NaCl-treated ischemic group (P<0.05). PGA may have high protective potential for different retinal layers and cells. Biochemical analysis of vitreous showed that all PGAs decreased vitreous XO activity significantly compared to the NaCl-treated group (P<0.05). However we could not find any statistically significant differences among the analogues. PGAs may reduce the injury induced by I/R, through the inhibition of XO activity, and it seems that their effects are elicited through numerous pathways.

Topics: Amides; Animals; Antihypertensive Agents; Apoptosis; Bimatoprost; Cloprostenol; Disease Models, Animal; Latanoprost; Male; Neuroprotective Agents; Prostaglandins F, Synthetic; Prostaglandins, Synthetic; Rabbits; Reactive Oxygen Species; Reperfusion Injury; Retina; Retinal Diseases; Travoprost; Vitreous Body; Xanthine Oxidase