Behavioural and morphological changes in rats with lead poisoning aggravated by medicinal hypothyroidism

Relevance. Metals are transported by run-off from human settlements and industrial plants and accumulate in the sediments of water bodies. Lead is found in high concentrations in the soil of agricultural land. Lead can be transported with water, seafood, animal products and plants to humans. Poisoning may occur in workers and in the population in contact with lead. At the same time, hypothyroidism is a widespread disease, often due to living in areas of endemic iodine deficiency in water and soil. Latent hypothyroidism can aggravate occupational effects of heavy metals in exposed workers.Intention. To study behavioural and morphological changes in rats with lead poisoning aggravated by medicinal hypothyroidism. Methodology. 32 albino outbred adult male rats were studied. Lead poisoning was induced by lead acetate at a dose of 60 mg/kg body weight in drinking water tanks for 30 days. Hypothyroidism in rats was induced from the ninth day of the experiment with daily injections of thyrozol (thyroid static substance) at a dose of 30 mg/kg for 21 days. Behavioral responses in rats were studied using open field tests, and survey records were processed using Real Timer. For morphological analysis, layered serial cuts of brain tissue were prepared and painted using the Nissl method, and slides were visualized via observation microscopy.Results and Discussion. Under lead poisoning, animals demonstrated decreased locomotor and exploration activity and increased anxiety with increasing intoxication combined with hypothyroidism. Changes in the rat brain after exposure to lead were confirmed histologically: increased neuron degeneration, neuronophagia and glyosis. New histological data were obtained in case of lead-thyrozol combination: increased neuronal death, decreased number of astroglial cells compared to animals exposed to lead only. This suggests predominant irreversible neurodegeneration due to combined effects of lead poisoning and thyroidstatic exposure.Conclusion. Under combined exposure to lead and tyrozol, the thyroidstatic substance exacerbated decline in locomotor and exploration activity as well as lead-associated neurodegenerative processes in the rat brain.