Morphological assessment of thyroid follicles in mature rats after chronic intoxication with toluene vapors and correction of changes with Echinacea purpurea

Introduction. The endocrine system is one of the first to react to changes in homeostasis, and the thyroid gland itself is a target for toxic substances, therefore, the study of its structural and functional organization under chronic inhalation exposure to toxic agents (in particular toluene) seems to be a topical issue for modern medicine. Of interest, as a therapeutic agent, is Echinacea purpurea which has been used for many years as an activator of adaptation mechanisms and a stimulant of the body’s protective functions in order to increase cellular resistance under stress. Aim. To study morphological changes in thyroid follicles of reproductive-aged rats after a 60-day intoxication with toluene and correction of changes with Echinacea purpurea, as well as to evaluate the dynamics and rate of their recovery 7, 15, 30 and 60 days after discontinuation of experimental exposure. Materials and methods. An experimental study was performed on 120 mature male rats. The animals were divided into 4 groups: group 1 – intoxication with toluene vapors at a concentration of 500 mg/m3 for 60 days; group 2 – control (intact animals); group 3 – toluene intoxication + Echinacea purpurea tincture at a dose of 200 mg/kg, intragastrically; group 4 – Echinacea purpurea tincture without toluene intoxication. Changes in the areas of follicles, colloid, follicular epithelium in the thyroid gland, as well as the follicular-colloid index were studied. Results. Morphological changes in thyroid follicles of mature rats after chronic intoxication with toluene vapors indicate a decrease in the functional activity of the organ. The colloid-epithelium ratio in the follicles changes. The maximum differences were revealed during the first week after discontinuation of toxic exposure: the colloid area increases by 25,13%, the epithelial area decreases by 21,37% and the follicular-colloid index – by 36,88%. The strength of the effect of toluene intoxication on all indicators is above 90%. In daily administration of Echinacea purpurea under toluene exposure, the growth of follicular epithelium and colloid resorption influencing the follicular-colloid index increases (rху = 0,93 and rху = –0,92, respectively). The effect of the herbal preparation persists for a month after discontinuation of experimental exposure: the colloid area decreases by 13,90%, and the follicular-colloid index increases by 21,50% compared to groups of rats that did not receive Echinacea purpurea during intoxication with toluene vapors. Conclusion. The experimental study confirmed the effectiveness of Echinacea purpurea in chronic exposure to toxic pollutants, which will contribute to the expansion of its use for medical and preventive purposes, in the combined treatment of endocrine diseases, and as well as to increase the tolerance, resistance and adaptive potential of the body to exogenous agents, in disorders both in the peripheral endocrine organs and in cell membranes and structural components of different cells of the body.