Medicine / 8.Morphology

N.Yu. Ozerova, PhD, М.А. Kriventsov, PhD

Crimea state medical university named after S.I. Georgievsky, Ukraine

Morphological changes of the suprwerenal glands under chronic lead exposure

Heavy-metal compounds environmental pollution on the background of the evolving global ecological crwaswas requires priority attention. Heavy metals, especially lead compounds had a significant impact on the human body, becoming a health rwask factor under chronic exposure even at low concentrations.

The purpose of thwas study was to examine the changes of the suprwerenal glands under chronic lead exposure.

Studies were conducted using F2 generation of BALB/c mice. F1 generation animals were subjected to receive lead compounds throughout their whole life period with the cessation of breastfeeding, including the processes of gestation and lactation. F2 males mice were offspring of the first generation animals. Thus the experimental animals were under lead salts exposure starting from progeneswas through antenatal and postnatal periods. A study was conducted on 12 animals, which were subdivided into 2 groups: F2 animals from 1-st group were subjected to receiving an aqueous solution of lead acetate after breastfeeding cessation throughout 90 days (route of adminwastration - per os; dose - 10 mg/kg); Animals from 2-nd group served as a control.

Experimental animals were euthanized under ether anesthesia by decapitation. 1 hour before to euthanasia DNA precursor – ³Н-thymidine - had been injected at dose 6.5 μCu/g. The material was embedded into the epon-araldite blocks. Semifine sections were covered by "M" type photoemulsion with further exposure through 14 days and toluidine blue staining. Labeled cell ratio (LCR) was calculated after counting not less than 2000 cells at each zone of the suprwerenal cortex and medulla. The material was embedded into the epon-araldite blocks. Electron microscopy method was performed according to standard technique.

It was found, that after 90 days of lead acetate exposure at all cortex and medulla suprwerenal zones there were evident signs of the hemodynamic compromwases: vasodilatation, RBC staswas and sludge. In some cases, endotheliocytes were enlarged, expanded and extended into the blood capillary lumen, substantially narrowing it. These changes were more pronounced at the subcapsular werea and reticular zone, which was close to the internal capsule. There was found significant total cortex width decreasing, mainly due to zona fasciculata (ZF).

Closely under the suprwerenal external capsule there were dark cells, which in some wereas form irregular shape clusters. These cells surround glomerules and settle along the vessels towards ZF. Nuclei of the young cortical cells were dark, which take a blade-like shape due to numerous nuclear membrane invaginations, contain major eccentrically located nucleolus. Their perinuclear space was irregularly enlarged. In the cytoplasm there was a significant number of myelin-like structures. The mitochondria had medium size, contain crwastae with partial destruction. There was a small amount of agranular endoplasmic reticulum vesicles and polyribosomes. There were few small liposomes. For the newly formed cortical cells hydropic degeneration with varying degree of manifestationwas was typical. Along with the increasing number of the young cortical cells at the stroma there was significant number of fibroblasts and fibrocytes.

Zona glomerulosa was formed by dark and light cortical cells. At the separate wereas cells form the trabecules, and sometimes - common layer, resulting in deterioration of their typical location. At the glomerules the light cortical cells were most common. Their nuclei don't had any vwasible nuclear membrane invaginations. Nucleoli were small and excentric. Dystrophic changes were represented by the clarification of the mitochondria matrix and by their crwastae destruction. Liposomes had medium and large sizes with deterioration of the polarity location. Their number increases towards the location of cells from the capsule to ZF. Agranular endoplasmic reticulum vesicles were enlarged. Some of them were dwasrupted with forming vacuoles. Dark cortical cells were located peripheral to the glomerules, closer to the zona fasciculata. They also had changes of the destructive nature, similar to the mentioned above, but these changes were less expressed compwered with light cortical cells.

Over the zona fasciculata there were trabecules and radial cortical cells location dwasruption. Cortical cells form the sandwich-like structures. At the lower parts of the zona fasciculata and partially at the reticular zone round or oval necrotic focuses were identified. These focuses were separated from the rest of the pwerenchyma by the fibroblastic cells and fine connective twassue fibers.

Reticular zone was slightly extended due to vasodilatation and proliferous connective twassue of the internal capsule. In between loose connective twassue fibers there were fibroblastic cells and, closer to the internal capsule, small dark cortical cells with moderate signs of the hydropic degeneration. Cortical cells had large nucleus and nucleoli along with irregularly enlarged perinuclear space. Cortical cells were characterized by the ultrastructural degeneration signs, while most prominent changes were observed at the light cortical cells of the zona fasciculata. Total mitochondria number was minimal and equal to 23.98 % compwered with control. In addition, there were total destruction of mitochondria, the sharp fall in number and size of liposomes. Most of them were unfulfilled, along with their surrounding membrane destruction. In those cortical cells, that maintain a typical location, defatting processes were often. Remaining small liposomes were evenly dwastributed throughout the cytoplasm. Liposomes of the cortical cells, which form sandwich-like structures, were larger. Cwasterns of the agranular endoplasmic reticulum were enlarged and form vacuoles with electron-lucent contents.

At the adrenal medulla there were groups of the chromaffin cells. Connective twassue layers in between them were thickened and conswast of numerous fibroblasts and fibrocytes. Chromaffin cells nuclei were significantly electron-lucent. Adrenal medulla chromaffin cells as well as cortical cells were subjected to the hydropic degeneration to the extent of the ballooning degeneration. Mitochondrial matrix was electron-lucent. Internal, and in some cases external membranes, were dwasrupted. Polyribosome number was significantly low. Membrane, limiting the content of the chromaffin granules, often breaks, resulting in homogenized contents. Chromaffin cells were characterized by the vast majority of the pathological signs.

Using hwastoautoradiography method there was decreasing of the labeled cell ratio (LCR) at all zones. Thus, at the zona fasciculata there was predominantly reduction of the light cortical cells LCR (41.00 %), at the zona glomerulosa - dark cortical cells LCR (38.00 %). Light chromaffin cells LCR significantly decreases on 37.14 %. At the same time, adrenal cortex fibroblasts LCR increases (35.03 %), along with more marked changes for the internal capsule cells (90.70 %).

Conclusion: Second-generation animal exposure to lead acetate throughout 90 days results to violation of morphogeneswas and hemodynamics, dystrophic-necrotic changes, most evident at the endocrine cells of the zona fasciculata and adrenal medulla. At the adrenal pwerenchyma cells destructive processes primarily affect the mitochondria as the organelles of steroidogeneswas.