| Abstract [eng] |
Phthalates are a group of man-made chemicals widely used as plasticizers in a wide variety of industries. These chemicals are known to disrupt the endocrine system and tend to accumulate in the body. With the increasing presence of these pollutants in the environment, it is very important to investigate their effects on various body systems, including the nervous system. The aim of this study was to determine the toxic effects of di(2-ethylhexyl) phthalate and dibutyl phthalate on the plasticity of the hippocampus in young rats. The experiment was approved by the Animal Ethics Committee of the State Food and Veterinary Service (2022-08/09 No. G2-221). To assess the neurotoxic effects of phthalates, histological analysis of the hippocampus of male rat pups was performed in two generations. Female rats of the Wistar strain aged 5–8 weeks were divided into 6 groups, which received standard food and an additional organic biscuit piece with different daily doses of phthalates dissolved in oil on each day of the experiment, depending on body weight and experimental group: 1) Control – received only biscuit with olive oil, 2) DEHP 200 µg/kg; 3) DEHP 1000 µg/kg; 4) DBP 100 µg/kg; 5) DBP 500 µg/kg; 6) phthalate mixture (DEHP 200 µg/kg, DBP 100 µg/kg). The female rats were fed in this manner for 3.5 months (2 months before pregnancy and 1.5 months during pregnancy and lactation). After weaning, the first-generation males were selected and euthanized using a CO2 chamber, while the females were left to repeat the same experiment in the second generation. After a period of time, the second-generation males were selected and euthanized after weaning. During necropsy, the brains of these animals were dissected, 5 µm thick histological sections were prepared, stained according to Nissl, and analyzed using the ImageJ system. Microscopy was used to evaluate changes in the thickness of the CA1/CA3 regions of the hippocampus and neuron density. Statistical differences were determined using GraphPad Prism 9.0.0. applying a one-way ANOVA. The results showed that a long-term daily dose of di(2-ethylhexyl)phthalate found in Lithuanian waters statistically significantly reduced the thickness of the CA3 region of the hippocampus and neuron density in the second generation, while a fivefold increase in the dose of this phthalate statistically significantly reduced the thickness of the CA3 region and neuron density in both generations and the CA1 neuron density in the first generation compared to the control group. Dibutyl phthalate statistically significantly reduced the thickness and neuron density of both hippocampal regions in both generations compared to the control group. |
