Histostructure of the internal organs and skin of rats for the long-term effect of the drug “VetMikoDerm”

Abstract

The investigation of the skin toxicity of the liniment “VetMikoDerm” for prolonged use was performed on young and healthy laboratory rats with intact skin, body weight 200–220 g. The investigated environment was applied to a clean, non-woolly area (dorsal/lateral surface) of at least 10% of the total surface area. The spotted thistle oil was applied to the pre-prepared area of the skin of the animals of the control group, and the other two experimental groups of animals got the studied drug at the doses of 50 (I) and 500 mg/kg (II), respectively. The drug was applied to the skin daily for 28 days. At the end of the experiment, after the decapitation of the rats conducted under the light etheric anesthesia, a complete pathoanatomical dissection was performed, the coefficients of the mass of the internal organs were determined, samples of liver, kidney and skin tissues were taken for their histological examination. According to the results it was established that the liver and kidneys histology, and skin of rats of the 1st experimental group were similar to those that were of the control animals. At the same time, receiving the maximum dose (10 times the therapeutic dose) of the drug “VetMikoDerm”, the majority of rats of the 2nd group showed a discomplication of the lamellar structure of the liver lobules, hepatocytes were placed in separate groups, sinusoidal capillaries were expanded. The presence of hepatocytes with heterogeneous, granular and weakly colored cytoplasm was observed in the central parts of the lobules, the nuclei of individual hepatocytes were increased, indicating the development of granular protein degeneration of the parenchyma. Histologically, under these conditions, foci of granular dystrophy of the epithelium of the vorticular and direct renal tubules with the expansion of their lumen were found in the structure of kidney of rats. The kernels of individual nephropyelitis had signs of karyopicnosis and cariorexis. The histological structure of skin of rats in all experimental groups was of the same type and consisted of the epidermis, dermis and hypodermis. Animals of the 2nd experimental group which repeatedly and for a long time were applied a “VetMikoDerm” lineulation in a dose that exceeded its optimal amount by 10 times showed the epidermal thickening, the presence of small-mesenchymal polymorphocytic infiltration, microcirculatory corneal disorder and sebaceous gland hyperplasia glands in the dermis that indicated the development of a compensatory-adaptive reaction in places of application of a 10-fold dose of the investigational medicinal product.