[Structural changes of eye chorioretinal complex after total cerebral ischemia and their correction].

Structural changes of eye chorioretinal complex were investigated in 40 adult male outbred albino rats after total transient cerebral ischemia using electron microscopy and morphometric analysis. Furthermore, the influence of a new sterically hindered phenolic antioxidant dibornol on these processes was estimated. Our studies demonstrated that total transient cerebral ischemia in rats resulted in the capillary thrombosis of the choriocapillary lamina of the uvea, structural disturbances of the blood-retinal barrier, degeneration of the retinal neurons and radial glia. Course administration of dibornol was shown to improve the microcirculation and to protect the retinal neuronal structures, pigment epithelium, and radial glia.

[Morphological changes in retinal neurons in rats with streptozotocin diabetes and their correction by O-isobornylphenol derivative].

Along with microangiopathy, degeneration of retinal neurons is one of the basic causes of blindness in patients with diabetic retinopathy. Using the electronic microscopy and morphometric analysis, the structural changes of neurosensory cells, associative and ganglionic retinal neurons were studied in 30 albino outbred male rats with long term (2 months) streptozotocin diabetes and the effect of a new semisynthetic antioxidant belonging to a group of strictly hindered phenols (4-methyl-2,6-diisobornylphenol) on these parameters was evaluated. In diabetic rats, the destructive changes of external segments of neurosensory cells and ganglionic retinal neurons were found. The numerical density of neurosensory and ganglionic cells was reduced, while the proportion of these cells with pyknotic nuclei was increased. 4-Methyl-2,6-diisobornylphenol demonstrated neuroprotective effect by preventing destructive changes of neurosensory cells and ganglionic retinal neurons.

[Changes of synaptoarchitecture of the retina after the light-induced damage and their correction by plant antioxidants].

The changes of interneuronal contacts in the internal reticular layer of albino rat retina were studied 7 and 30 days after the exposure to high intensity light (6000 Lux for 6 h). In osmicated preparations, the "light" type of synapse destruction was predominant 7 days after the light-induced damage. Using the contrasting by phosphotungstic acid, paramembrane structures of the system of subsynaptic units--dense projections and postsynaptic condensations of synapses--were studied. It was found that the exposure to high intensity light resulted in the destructive changes of synapses and the decrease of their numeral density at the expense of the actively functioning symmetric contacts. 30 days after the light-induced damage, the numeral density of symmetric contacts was significantly increased, while the content of symmetric mature synapses was decreased. Course administration of ascovertine and carovertine before and after the exposure to light was found to have a differential effect on limiting the destruction of the synapses and on the activation of the repair mechanisms which are realized due to the hypertrophy and neosynaptogenesis. The highest effect was found after carovertine administration.

[Structural changes of the retina and corpus vitreum in the model of proliferative vitreoretinopathy in alloxan diabetes].

The present study was conducted to determine the role of blood mononuclear cells in a morphogenesis of proliferative vitreoretinopathy (PVR) and to detect the peculiarities of PVR development in hyperglycemia. Experiments were performed in 75 mature male Wistar rats. In animals of group 1, the model of PVR was reproduced by injection of mononuclear cells into the corpus vitreum. In animals of group 2, alloxan diabetes was induced 6.5 weeks prior to intravitreal injection of mononuclear cells. The material obtained was studied using the methods of light and electron microscopy. Development of PVR by intravitreal injection of mononuclear cells in diabetic rats was found to be associated with more severe destructive and proliferative changes. Considering the integrative role of blood mononuclear cells in the intercellular networks, it is suggested that these cells are involved in the pathogenesis of PVR.

[The damage of the neural retina and of the retinal pigment epithelium of eyes of rats exposed to highly intensive visible light under alloxanic diabetes].

The experiments on white mongrel rats showed that the light with the intensity of 6000 1x lasting for 6 hours resulted the destruction of the retinal pigment epithelium, of the internal and the external neurosensory cellular processes with subsequent nuclei piknosis and radial glia replacement. On the 7th day after exposure to light focal effusion of the retina corresponding layers. Under the irradiation in diabetes the amount of cells with karyopyknosis increases in 1.6 times in comparision with the findings in case free of diabetes. Was found, that the alloxanic diabetes in its early stage increases the light impairment of the neurosensory cells of the retina.

[Effects of combined influence of ionizing radiation and light on the retina]. / Effekty kombinirovannogo vozdeistviia ioniziruiushchei radiatsii i sveta na setchatku glaza.

The continuous irradiation of rats with a light (3500 1x) for 48 hours led to destruction of 7.5 +/- 0.43% of neurosensoric cells (the control value was 0.2 +/- (0.02%). Longer photodamage caused progressing decrease in a population of the cells, narrowing followed by disappearance of corresponding layers of retina by the 30th day of the experiment. Preliminary exposure to X-rays with a dose of 5 Gy modified light damages of retina. The combination of two factors caused death of more than 30% of neurosensoric cells and redused the number of rows of nucleis of the external nuclear layer twice for the first 48 hours of illumination. After a longer influence of light a preliminary ionizing irradiation increased the number of destructively changed neurosensoric cells, reaching minimun of 41.7% by 30th day of the experiment. At the same time after a long combined irradiation less changes in row number quantity, numerical density of nucleus of the external nuclear layer and a population of neurosesoric cells in general was observed than after only one light exposure. Changes of choriocapillaries (thrombosis, obliteration, narrowing of a gap) which were more expressed at a combination of factors, led to infringement of blood circulation and played the important role in mechanisms of retina degeneration. Radial glia and neurons of internal layers of retina showed relative resistance to the investigated influences.