Mitochondria-targeted cationic plastoquinone derivative SkQ1 (10-(6'-plastoquinonyl) decyltriphenylphosphonium) has been investigated as a potential tool for treating a number of ROS-related ocular diseases. In OXYS rats suffering from a ROS-induced progeria, very small amounts of SkQ1 (50 nmol/kg per day) added to food were found to prevent development of age-induced cataract and retinopathies of the eye, lipid peroxidation and protein carbonylation in skeletal muscles, as well as a decrease in bone mineralization. Instillation of drops of 250 nM SkQ1 reversed cataract and retinopathies in 3-12-month-old (but not in 24-month-old) OXYS rats. In rabbits, experimental uveitis and glaucoma were induced by immunization with arrestin and injections of hydroxypropyl methyl cellulose to the eye anterior sector, respectively. Uveitis was found to be prevented or reversed by instillation of 250 nM SkQ1 drops (four drops per day). Development of glaucoma was retarded by drops of 5 microM SkQ1 (one drop daily). SkQ1 was tested in veterinarian practice. A totally of 271 animals (dogs, cats, and horses) suffering from retinopathies, uveitis, conjunctivitis, and cornea diseases were treated with drops of 250 nM SkQ1. In 242 cases, positive therapeutic effect was obvious. Among animals suffering from retinopathies, 89 were blind. In 67 cases, vision returned after SkQ1 treatment. In ex vivo studies of cultivated posterior retina sector, it was found that 20 nM SkQ1 strongly decreased macrophagal transformation of the retinal pigmented epithelial cells, an effect which might explain some of the above SkQ1 activities. It is concluded that low concentrations of SkQ1 are promising in treating retinopathies, cataract, uveitis, glaucoma, and some other ocular diseases.

Cells have intrinsic mechanisms for cleaning harmful oxidants represented mainly by reactive oxygen species (ROS). Despite the antioxidant defense, ROS can cause serious damage to the retina that with age leads to various eye diseases and even blindness. Among numerous cell sites of ROS generation, mitochondrial electron transport is of crucial importance. Recently, for the purpose of cleaning ROS in the mitochondrial matrix, powerful mitochondria-targeted antioxidant "SkQ1" has been invented. We studied SkQ1 effects upon tissues of rat posterior eye cup that consisted: retinal pigment epithelium (RPE) ↔ choroidal coat ↔ scleral coat. The eye cups were isolated from the eyes of adult albino rats and cultivated in rotary tissue culture system in the presence of 20 nM SkQ1 or without this compound. After 7 days -1 month in vitro eye cup samples were studied by immunohistochemistry, routine histology, morphometry, and digital image analysis. We have found that under chosen, "in vitro like in vivo" conditions 20 nM SkQ1 effectively reduced cell death in RPE and choroid, protected RPE from disintegration caused by cell phenotypic transformation and withdrawal from the layer, suppressed transmigration of choroidal coat cells. In the ex vivo model we used degenerative processes were more pronounced in the eye cup center where SkQ1 effect was most vivid. All this give us hopes for effectiveness of SkQ1 treatment of retinal central part that is very susceptible to light-induced over-oxidation injury and mostly suffering in many age-related diseases, AMD, in particular.

We propose a new method of organotypic roller 3D-culturing of the posterior sector of the eye. The method allows maintaining tissue viability in vitro for 14 days (which considerably surpasses the capacities of stationary culturing) and studying of the behavior, of pigment retinal epithelial cells and choriocapillary membrane. Using this method we demonstrated phenotypic transformation, migration, and proliferation of pigment retinal epithelial cells under conditions of roller organotypic culture. In the absence of the retina, these cells exhibit properties of scavenger cells (phagocytes) both within and outside the layer. Under conditions of roller culturing in vitro, cells of the pigment retinal epithelium undergo changes similar to those observed in various retinal pathologies in vivo, including age-associated changes. Here we discuss the possibility of using the proposed method for evaluation of the effect of various factors added to the culture medium on the pigment epithelium, for modeling of processes developing in damaged pigment epithelium or under conditions of various pathologies, and for the study of regeneration responses in cells of pigment retinal epithelium in adult vertebrates.

During life human eye is constantly exposed to sunlight and artificial light, the sources of reactive oxygen species (ROS)-the main cause of age-related eye pathology. A novel mitochondria-targeted antioxidant SkQ1 has recently been invented to reduce mitochondrial ROS by cleaning the mitochondria matrix, "the dirtiest place in the cell" in respect of ROS production and accumulation. Earlier we studied SkQ1 effects upon retinal pigment epithelium and choroid in the rat eye posterior cups exposed to long-term 3D organotypic culturing. It was found that under in vitro conditions 20 nM SkQ1 effectively reduced cell death in retinal pigment epithelium and choroid and protected the tissues from disintegration and cell withdrawal. In the present study we used same ex vivo conditions to examine the effect of SkQ1 upon the rat neural retina kept in the content of the posterior eye cup. Eye cups were isolated and cultured in vitro during 7, 14, and 30 days under rotation in the presence and absence of 20 nM SkQ1 in the culture medium. Serial sections of cultivated eye cups were subjected to histology, computer morphometry and immunohistochemistry. Obtained results show that SkQ1 operates as a strong protective agent, preventing neuronal cell death and other degenerative processes in the neural retina. Cell rescue by SkQ1 was more vivid in the central part of the retina than at the periphery. That, in turn, suggests SkQ1 effectiveness in treatment of some age-related eye diseases when central part of the retina, including macula, is most susceptible to degeneration.