RU2498415C1 - Method for simulating diabetic macular oedema - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: alloxan is introduced into rat's peritoneum in a dose of 15.0 mg/100 g of weight. Then, 6.5 weeks after alloxan has been introduced, and experimental diabetes has been developed, insulin-like growth factor 1 (IGF-1) 1 mcl is introduced into the vitreous body from an intravitreous approach.

EFFECT: method simplifies and reduces the length of formation of persistent primary macular oedema specific for diabetes mellitus, enables analysing the course of the pathological process, forming the new therapeutic regimens.

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Description

The invention relates to medicine, in particular to ophthalmology, and can be used to create a model of diabetic macular retinal edema in experimental ophthalmology.

A known method of creating an experimental model of insulin-dependent diabetes mellitus by a single intraperitoneal injection of alloxan hydrate in experimental animals at a dose of 170 mg / kg Alloxan used in modeling diabetes mellitus generates toxic free radicals that damage Langerhans B cells, kidney, liver, lung cells, and adipocytes (Szkudelski T. The mechanism of alloxan end streptozotocin action in B cells of the rat pancreas // Physiol. Res. - 2001. - No. 50. - P.536-546.). In alloxan diabetes, oxidative stress occurs in adipose tissue, characterized by an increase in the content of lipid peroxidation products in it and a violation of thiol disulfide metabolism. Activation of lipid peroxidation and a decrease in the antioxidant potential of the glutathione system in rat adipose tissue in experimental diabetes can lead to stimulation of spontaneous lipolysis in adipocytes and insulin resistance (Ivanov V.V. et al. Lipid peroxidation and glutathione system in rat adipose tissue with alloxan diabetes // Bulletin of the SB RAMS. - 2010. - 30, No. 6. - P.101-104.). When modeling diabetes in an experiment, pathological changes in the fundus do not appear, because for the process of proliferation in the vitreous to occur, it takes up to 2 years, which greatly complicates the experiment.

The closest analogue of the invention is a method for reproducing age-related edema of the macula by intravitreal administration of vascular endothelial growth factor VEGF 164 (Vascular endothelial growth factor) to rabbits. This method is not etiotropic for diabetes, because reproduced in the absence of hyperglycemia. Pathological changes that occur on the fundus during histological examination do not coincide with the diabetic lesion of the macular zone.

To date, it has been proven that pathological changes in the macular region of the retina are directly related to the level of the insulin-like factor - 1 (Insulin-like growth factor - 1) - IGF-1 (Ringholm L., Vestgaard M., Laugesen CS, Juul A., Damm P., Mathiesen ER Pregnancy-induced increase in circulating IGF-I is associated with progression of diabetic retinopathy in women with type 1 diabetes / Growth Horm IGF Res. No. 21 (1), 2011. P.25-30). Elevated levels of IGF-I are an indicator of pathological changes in the retina in type I and type II diabetes mellitus. At the same time, between the diabetic edema of the macular region and this growth factor, a direct etiopathogenetic dependence was determined, both direct and inverse.

The task of the invention is to develop a reliable, technically simple method for modeling diabetic macular edema in an experiment.

The technical result when using the invention is the formation of macular diabetic edema, the etiotropy of pathological changes in the macular zone with common endocrine disorders.

The proposed method for modeling diabetic macular edema is as follows: experimental animals are injected into the abdominal cavity with alloxan at a dose of 15.0 mg / 100 g weight. Animals are monitored until the development of signs of diabetes - 6.5 weeks. 6.5 weeks after the administration of alloxan and the development of experimental diabetes mellitus, intravitreal injections are performed for each animal under ether anesthesia: insulin-like growth factor-1 (IGF-1) is introduced through the flat part of the ciliary body at a dose of 1 μl at a distance of 1 mm from the lower limb -secondary sector.

For control, an indirect ophthalmoscopy is performed on the 3rd, 7th and 14th day after injection under conditions of drug mydriasis (S.Tropicamidi installations 1%) and histological studies on the 15th day. The technique was tested on 93 male Wistar rats weighing 200 g. Animals were removed from the experiment by air embolism after being anesthetized on the 15th day, eyes were enucleated (according to the order of the USSR Ministry of Higher Education No. 724 of 11/13/1984). For morphological studies on a microtome, serial sections of 7–10 μm thick were prepared. Histological sections were stained with hematoxylin-eosin.

The combination of two components in one model (experimental diabetes mellitus and intravitreal administration of IGF-1) gives the development of persistent diabetic macular edema. The action of alloxan and an insulin-like factor determines the unidirectionality of the pathological process, characterized by manifestation at the local and general level. The growth factor IGF-1 becomes the trigger for the development of macular edema, because acts against the background of general hyperglycemia.

The result of using such a model is the development of edema, directed along the classical path. At the histological level, in the zone of the photoreceptor layer, cavities are formed in the form of cysts, drusen. In 34%, they are combined into one conglomerate, manifested by local retinal detachment. Changes in the pigment epithelium layer are typical of diabetic macular edema. When using this model, traction from the vitreous body was not detected, which characterizes this diabetic edema as primary.

Example.

The proposed method is illustrated by the following example: a male Wistar rat, weighing 174 grams, reproduced diabetes after 24 hours of fasting by intraperitoneal administration of alloxan at a dose of 15.0 mg / 100 g weight. 6.5 weeks after the administration of alloxan and the development of experimental diabetes mellitus, the animal under ether anesthesia was administered IGF-1 in a dose of 1 μl through the flat part of the ciliary body. Then the animal was removed from the experiment by the method of air embolism after anesthesia (according to the order of the USSR Ministry of Higher Education No. 724 of 11/13/1984) on the 15th day. Histologically, on the 15th day of the experiment, according to light microscopy, retinal edema with cysts of the outer plexiform layer and destruction of the pigment epithelium were determined on sections of the central region of the retina. The height of the edema was 370 microns. In the choroid zone, pathological lesions were not detected.

Claims (1)

A method for modeling diabetic macular edema, including intravitreal administration of a toxic agent to an experimental animal, characterized in that a rat is used as an experimental animal, with alloxan being preliminarily introduced into the abdominal cavity at a dose of 15.0 mg / 100 g weight, 6.5 weeks after administration of alloxan and the development of experimental diabetes mellitus, insulin-like growth factor-1 (IGF-1) is administered as a toxic agent at a dose of 1 μl.