Histološke i ultrastrukturne promene hipofize i nadbubrežnih žlezda pacova u uslovima akutnog toplotnog stresa

Abstract

Ispitivan je uticaj akutnog toplotnog stresa na histološke, imunohistohemijske, ultrastrukturne, stereološke i biohemijske karakteristike adrenokortikotropnih ćelija hipofize i ćelija nadbubrežnih žlezda pacova kao ciljnih organa hipotalamo-hipofizne-adrenalne osovine u odgovoru na dejstvo stresora. Pacovi mužjaci soja Wistar izlagani su temperaturi od 38C u komori u trajanju od 60 minuta. Životinje su nakon tretmana žrtvovane dekapitacijom u prepodnevnim časovima, u približno isto vreme, da bi se izbegao uticaj cirkadijalnog ritma na proučavane parametre. Kortikotropne ćelije adenohipofize su analizirane na nivou svetlosne i transmisione elektronske mikroskopije primenom imunohistohemijskih i stereoloških metoda. U nadbubrežnim žlezdama ispitivane su histološke i ultrastrukturne karakteristike ćelija kore i srži. Kvantitativne odlike nadbubrežnih žlezda određivane su primenom stereoloških i morfometrijskih metoda na nivou svetlosne i elektronske mikroskopije. Peptidergički neuroni (VIP, SP i NPY) u kori i srži nadbubrežnih žlezda procenjivani su imunohistohemijskim metodama. Za prikazivanje protoka krvi u nadbubrežnim žlezdama korišćena je Noveli histološka metoda bojenja. Ćelije u proliferaciji procenjivane su preko Ki-67 antigena, dok je za detekciju apoptotskih ćelija nadbubrežnih žlezdi primenjeno bojenje propidijum-jodidom. Određivane su i koncentracije adrenokortikotropnog hormona hipofize (ACTH), kao i kortikosterona, aldosterona, adrenalina i noradrenalina nadbubrežnih žlezda pacova u cirkulaciji. U hipofizi, primenjeni tretman doveo je do povećanog izlučivanja ACTH iz kortikotropnih ćelija. Ovo se na nivou svetlosne mikroskopije manifestovalo smanjenjem broja ćelija imunopozitivnih na ACTH, a na nivou elektronske mikroskopije smanjenjem broja granula u ACTH ćelijama. U skladu sa tim, biohemijski podaci pokazali su da je koncentracija ACTH u cirkulaciji povećana. U krvnim sudovima hipofize prisutna je agregacija krvnih pločica...

The aim of the study was the effect of acute heat stress on the histological, immunohistochemical, ultrastructural, stereological and biochemical characteristics of corticotroph pituitary cells and cells of the adrenal glands of rats as a target organ of the hypothalamic-pituitary-adrenal axis in response to the effects of stressors. Wistar male rats were exposed to a temperature of 38C in the chamber for 60 minutes. Animals were sacrificed by decapitation after treatment in the morning, at about the same time, in order to avoid the influence of circadian rhythm on the studied parameters. Corticotroph pituitary cells were analyzed at the level of light and by transmission electron microscopy using immunohistochemical and stereological methods. The adrenal glands were studied by histological and ultrastructural characteristics of the cells of cortex and medulla. Quantitative characteristics of the adrenal glands were determined using stereological and morphometric methods at light and electron microscopy. Peptide neurons (VIP, SP and NPY) in the cortex and medulla of the adrenal glands were assessed by immunohistochemical methods. To show the flow of blood to the adrenal glands a Novelli histological method of staining was used. The cells in proliferation were assessed by Ki-67 antigen, whereas the detection of apoptotic cells of the adrenal gland was enabled by propidium-iodide staining. The concentration of pituitary adrenocorticotropic hormone (ACTH) and corticosterone, aldosterone, adrenaline and noradrenaline in the rat adrenal gland circulation were determined. In the pituitary, the applied treatment resulted in increased secretion of ACTH from corticotroph cells. On the level of light microscopy, it was demonstrated by decreased number of immunopositive ACTH cells, and at the level of electron microscopy by reduced number of granules in the ACTH cells. Accordingly, biochemical data showed that the concentration of ACTH in the circulation increased. The blood vessels of the pituitary gland in platelet aggregation were present...