EFFECT OF L-TOCOPHEROL-CORRECTOR ON MORPHO-FUNCTIONAL ADJUSTMENT OF RAT’S ADRENAL GLANDS UNDER CONDITIONS OF READAPTATION TO LONG-TERM EXPOSURE OF HEAVY METAL SALTS

Abstract

The monograph presents a theoretical generalization and scientific solution of a comprehensive study of the structural components state of the mature rats adrenal cortex under conditions of adaptation to the long-term influence of heavy metal salts and correction with L-tocopherol. The experiment was carried out on 24 white sexually mature male rats at the age of 7-8 months. The animals of the experimental group consumed ordinary drinking water for 30 days with the corrector drug L-tocopherol after 90 days of receiving water saturated with a combination of salts of heavy metals: zinc (ZnSO4 7H2O) – 5 mg/l, (CuSO4 5H2O) – 1 mg/l, iron (FeSO4) – 10 mg/l, manganese (MnSO4 5H2O) – 0.1 mg/l, lead (Pb (NO3)2) – 0.1 mg/l and chromium (K2Cr2O7) – 0.1 mg/l. The keeping of animals and all manipulations over them were carried out in accordance with national and international bioethical standards. To study morphological rearrangements in the adrenal cortex, histological, morphometric, immunohistochemical and biochemical research methods were used. Sections were stained with hematoxylin-eosin, Einarson, and Van Gieson’s. The expression of the proliferation marker Ki-67 and the heat shock marker 90 (Hsp90α) was determined on dewaxed sections 4-5 μm thick according to the manufacturer’s recommendations. The restoration of the histostructure of the adrenal cortex testified to the development of adaptive and regenerative processes in the organ, aimed at neutralizing the stress response and a number of hypoxic phenomena caused by the longterm influence of heavy metal salts. Adaptive rearrangements affected morphological changes in all structural components of the adrenal glands of experimental animals: stromal, vascular, and parenchymal. The corrector drug L-tocopherol had a bright protective effect on the structural components of the adrenal glands, taking into account its antioxidant properties, membrane-protective effect, etc. The positive adaptive morphological rearrangements in the adrenal glands can include a slight compensatory hypertrophy of the adrenal cortex, an increase in the functional activity index of the glomerular and reticular zones, a decrease in the severity of the fibrous component of the connective tissue of the stroma, the disappearance of stromal edema, stabilization of the circulatory system and rheological properties of the blood, improvement of the cytoarchitectonics of all zones cortex, the appearance of mitotic figures in the cells. There was a significant improvement in the state of the chromatin network of the nuclei of corticocytes and the appearance of nucleoli in most of the nuclei. The mechanisms of endocrine regulation of adaptive processes after prolonged exposure to salts of heavy metals in the body of experimental animals also worked due to the activation of the synthesis of sex hormones. An increase in Hsp90α expression in adrenal corticocytes also indicated active adaptive processes in their cytoplasm aimed at restoring synthetic activity. Despite the positive rearrangements in the adrenal cortex, negative signs should also be noted, namely: stromal edema and moderate vascular plethora were still present in the reticular zone, although the severity of these morphological rearrangements decreased in comparison with the indicators of animals with a 90-day period of consumption of heavy metal salts. The positive dynamics of the development of adaptive processes in the adrenal glands suggests that in the future, an increase in the timing of readaptation with the use of L-tocopherol can positively affect the achievement of homeostasis in the organ and lead to full or partial compensation for the action of the damaging agent on the organism of experimental animals.