Retinal changes after intravitreal injections of various concentrations of antiproliferative medication Melphalan: an experimental and morphological study

Proliferative vitreoretinopathy is a multifactorial pathological process of formation of epiretinal membranes on the surface of the retina. The main method of treatment of this disease is vitreoretinal surgery. To increase the effectiveness of treatment, intravitreally administered antiproliferative drugs are used. Purpose: to study the effect of intravitreally administered medication Melphalan in varied concentrations on the retina and retinal pigment epithelium (RPE), in the experiments on rabbits. Materials and Methods. An experimental morphological study was performed on 28 eyes of 14 Chinchilla rabbits, divided into 4 groups depending on the concentration of Melaphan (0.02 mg, 0.01 mg, 0.0075 mg and 0.005 mg) administered intravitreally once. Results. Four types of morphological changes in the retina and RPE are described, depending on the medication dose administered. The target of Melphalan accumulation in the retina is RPE, which brings about metabolism disorders in the outer layers of the retina and the appearance of atrophic foci. The dynamics of these foci and their reversibility is discussed. Conlusion. The study of morphological changes of the retina in cases of introvitreal administration of Melphalan showed that they are dose-dependent. The minimum retinal toxicity is observed when low concentrations of the drug are used: 0.0075 and 0.005 mg. For citation: Khoroshilova-Maslova I.P., Leparskaya N.L. Retinal changes after intravitreal injections of various concentrations of antiproliferative medication Melphalan: an experimental and morphological study. Russian ophthalmological journal. 2018; 11 (1): 36-40. doi: 10.21516/2072-0076-2018-11-1-36-40 (In Russian)

The role of platelet-derived growth factor in pathobiology of epiretinal membranes in proliferative vitreoretinopathy (an experimental morphological study)

Proliferative vitreoretinopathy (PVR) is a pathological process based on proliferation of retinal pigment epithelium (RPE) cells and glia on the interior surface of the retina accompanied by epiretinal membrane formation. The condition’s pathogenesis remains unclear. The best-founded hypothesis is that PVR pathogenesis involves growth factors and cytokines with the key role of platelet-derived growth factor (PDGF). The purpose of this work is an experimental morphologic study of changes in eye tissues after they were treated by recombinant PDGF administered intravitreally. Material and methods. 6 Chinchilla rabbits (12 eyes) were given intravitreal injections of 0.1 ml of PDGF through the flat part of the ciliary body. The concentrations were 2000 mg/ml (4 eyes), 5000 mg/ml (4 eyes), and 20000 mg/ml (4 eyes). Microscopic observation of the eyes, enucleated one month after the procedure was performed with a Leica microscopic system supplied with a digital camera with a x200-x600 magnification. Results. RPE was found to be the main target of PDGF. The impact was revealed to be dose-related. With doses of 2000 mg/ml and 5000 mg/ml retinal epithelial cells are dissociated, rounded, they form processes, fall out of the sheet and migrate to the surrounding area. With big doses (20000 mg/ml), death of photoreceptor cells in the retina occurs along with extensive migration of cells and Bruch's membrane denudement. The mechanism underlying migration processes, associated with the influence of PDGF on the system of counter-adhesive proteins is discussed. Conclusion. The role of migration of RPE cells induced by PDGF in the formation of the early stage of PVR was demonstrated // Russian Ophthalmological Journal, 2016; 4: 59-63. doi: 10.21516/2072-0076-2016-9-4-59-63