An important task of pharmacology and ophtalmology is to find specific and highly effective agents for correcting retinal ischemia. The objective of this study is to increase the effectiveness of pharmacological correction of retinal ischemia by using new 3-hydroxypyridine derivative–l-isomer of ethylmethylhydroxypyridine malate. A modification to the retinal ischemia-reperfusion model was used, in which an increase in intraocular pressure is carried out by mechanical pressure (110 mmHg) to the front chamber of the eye for 30 min. The protective effects of l-isomer of ethylmethylhydroxypyridine malate in comparison with Emoxipine as pretreatment, with parabulbar injection, based on the model of retinal ischemia-reperfusion, were estimated by the changes in the ratio of the amplitudes of the a- and b-waves of electroretinography (the b/a coefficient) and ophthalmoscopy. The use of l-isomer of ethylmethylhydroxypyridine malate improves the retinal electrophysiological state after 72 h of reperfusion; in the group of rats treated with l-isomer of ethylmethylhydroxypyridine malate, the coefficient b/a was reliably increased by 9.5%, p < 0.05, in comparison with animals treated with Emoxipine, and by 91.7%, p < 0.05, in comparison with the group with no treatment. Furthermore, it prevents the development of ischemic changes in the retina observed in ophthalmoscopy to a greater extent than Emoxipine.
An important task of pharmacology is to find effective agents to improve retinal microcirculation and resistance to ischemia. The purpose of the study is to pharmacologically evaluate the retinoprotective effect of 2-ethyl-3-hydroxy-6-methylpyridine nicotinate in a rat model of retinal ischemia–reperfusion. A retinal ischemia–reperfusion model was used, in which an increase in intraocular pressure (IOP) to 110 mmHg was carried out within 30 min. The retinoprotective effect of 2-ethyl-3-hydroxy-6-methylpyridine nicotinate at a dose of 3.8 mg/kg, in comparison with nicotinic acid at a dose of 2 mg/kg and emoxipine at a dose of 2 mg/kg, was estimated by the changes in the eye fundus during ophthalmoscopy, the retinal microcirculation level with laser Doppler flowmetry (LDF), and electroretinography (ERG) after 72 h of reperfusion. The use of 2-ethyl-3-hydroxy-6-methylpyridine nicotinate prevented the development of ischemic injuries in the fundus and led to an increase in the retinal microcirculation level to 747 (median) (lower and upper quartiles: 693;760) perfusion units (p = 0.0002) in comparison with the group that underwent no treatment. In the group with the studied substance, the b-wave amplitude increased significantly (p = 0.0022), and the b/a coefficient increased reliably (p = 0.0002) in comparison with the group with no treatment. Thus, 2-ethyl-3-hydroxy-6-methylpyridine nicotinate has established itself as a potential retinoprotector.
Introduction:Retinoprotective effects of non-selective imidazoline receptor agonists: potassium salt of С7070; sodium salt of С7070; С7070 processed with CO 2 -were investigated in comparison with C7070 on the retinal ischemia-reperfusion model in rats. Materials and methods:The protective effects of the substances were evaluated by using ophthalmoscopy, laser Doppler flowmetry, electroretinography, histological and morphometric studies of retinal layers. Results and discussion:The most pronounced retinoprotective effect was observed in potassium salt of C7070 at a dose of 10 mg/kg, which expresses in approaching the normal eye fundus image, achieving the target values of the retinal blood flow, b/a coefficient, and reaching the norm values of morphometric indicators. A less pronounced protective effect was found in sodium salt of C7070 at a dose of 10 mg/kg, which expresses in a 71% decrease (p < 0.05) in semi-quantitative assessment of the eye fundus changes, an increase in the retinal blood flow level by 70.4% (p < 0.05), in b/a by 94% (p < 0.05) in comparison with the group without correction, and reaching the norm of the morphometric indicators. A retinoprotective effect of the substance C7070 processed with CO 2 at a dose of 10 mg/kg is inferior to that of the sodium salt of C7070. Conclusion:The retinoprotective activity of the substances is expressed in descending order: potassium salt of С7070 (10 mg/kg) ≈ С7070 (50 mg/kg) > sodium salt of С7070 (10 mg/kg) > С7070 processed with CO 2 (10 mg/kg) ≈ С7070 (10 mg/kg). Injections of glibenclamide leveled the neuroretinoprotective effects of the substances to varying degrees, which confirmed the participation of ATP-dependent potassium channels in the implementation of these effects.
Introduction: The retinoprotective effect of the 11-amino acid fragment of darbepoetin PRK-002 on the models of hypertensive retinal angiopathy and hypertensive neuroretinopathy in Wistar rats was investigated in comparison with carbamylated darbepoetin and sulodexide. Materials and methods: The protective effects of the pharmacological agents were assessed using the following criteria: a semi-quantitative assessment of changes in the eye fundus when performing ophthalmoscopy, the retinal blood flow, the b/a coefficient, eNOs expression in retinal vessels, specific number of neuronal nuclei in the inner nuclear layer, and p53 expression in the retina. Results and discussion: A pronounced protective effect, exceeding sulodexide at a dose of 150 LRU/kg and carbamylated darbepoetin at a dose of 300 μg/kg when correcting retinal angiopathy was observed in PRK-002 at a dose of 4 µg/kg, which expressed in adjustment of the retinal vessels’ calibers, removing retinal arterio-venous crossings, reaching the target levels of the retinal microcirculation, the b/a coefficient, and the restoration of eNOs expression in the endothelium of retinal vessels. PRK-002 at a dose of 4 µg/kg has a pronounced neuroprotective effect comparable to carbamylated darbepoetin at a dose of 300 µg/kg in correction of hypertensive neuroretinopathy, which expressed in the normalization of the fundus image, reaching the b/a target values, the specific number of neuronal nuclei in the inner nuclear layer, inhibition of p53 expression in the neurons of the inner nuclear and ganglionic layers. Conclusion: The study revealed angio- and neuroprotective activity of the 11-amino acid fragment of darbepoetin PRK-002 in correction of retinal injury formed on the background of hypertension.
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