Our study investigated morphological changes in enterocytes of adult Japanese quails that were given cadmium (CdCl2) perorally and individually by tube, dissolved in water at a dose of 0.24 mg Cd per animal per day, for 57 and 118 days. The aim of our study was to observe chronic effects of cadmium on the structure of duodenal epithelium by means of light microscopy (LM) and transmission electron microscopy (TEM). On day 57, following peroral administration of cadmium, necrotizing enterocytes were found in the apical part of intestinal villi and their occurrence was only sporadic. Particularly on day 118 following cadmium administration, we were able to observe clusters of 2-3 necrotizing cells in the apical part of intestinal villi. However, the structure and ultrastructure of goblet cells was normal. The most notable finding in ultrastructure of all enterocytes of treated animals was the damage to cell organelles. Mitochondria and cisternae of the endoplasmic reticulum were more or less damaged and the cytoplasm contained flocculent material, particularly in the basal part of enterocytes. Some enterocytes exhibited signs of necrosis, shrivelled nucleus and damaged organelles within the markedly electrondense cytoplasm. Microvilli on the apical surface of these enterocytes were damaged and disintegrated. Junctions between cells of the intestinal epithelium were disturbed, and a present of intracellular plaques associated with the adhering and occluding junctions was observed. Cadmium caused the formation of gaps within the specialized junctional complexes, and injury to enterocytes results in the breakdown of the intercellular attachments and the sloughing of the injured cells into the intestinal lumen.

Morphological Changes in Duodenal Epithelium of Japanese Quail after Chronic Cadmium Exposure

Exposure to cadmium (Cd) is known to alter immune responses. Acanthopanax senticosus (Rupr. et Maxim.) Harms (AS) extract, an antioxidant-containing complex of phenolic compounds, tetracyclic triterpenoids/steroids, and polysaccharides, is known to produce Cd mobilization and excretion in vivo. Building upon earlier findings, the aim of the study was to evaluate the effects of an AS extract on Cd accumulation and changes in the presence of splenic immune cells in hosts during a chronic metal exposure. Chronic Cd exposure of BALB/c mice was induced by providing them solutions containing different levels of CdCl2 (25 or 250 mg/L) in double-distilled water, with/without a concurrent presence of AS root extract (approximately 151 g material/L), for 8 wk. At the study end, Cd levels in spleen were measured. Levels of key splenic immune cells, including macrophages, T-lymphocytes, and B-lymphocytes, were determined by immunohistochemistry using, respectively, CD68, CD3, and CD20 antibodies. The results indicated that chronic consumption of AS extract in the presence of the high dose of CdCl2 led to a significant decrease in Cd levels in mouse spleen. The effects of AS on the lower CdCl2 dose were less apparent. In addition, the presence of AS and Cd increased the amount of macrophages and both B and T lymphocytes in mouse spleen relative to concentrations that were lowered as a result of chronic metal only intake.

Effect of Acanthopanax senticosus on the accumulation of cadmium and on the immune response of spleen cells.

We observed the effect of cadmium (Cd group) and cadmium+zinc (Cd/Zn group) in the liver of turkeys after a 71-day exposure. The experimental birds were divided to three groups; control group (Control), group exposed to cadmium (group Cd) as CdCl2 (aqueous solution, 0.5 mg/kg feed); and group Cd/Zn exposed to the same dose of cadmium as Cd group plus zinc as ZnSO4 (aqueous solution, 90 mg/kg feed). Light and electron microscopy revealed pronounced changes in the liver of turkeys from the Cd group, such as hyperaemia, dilatation of sinusoids and accumulation of inflammatory cells, including macrophages, heterophils, and lymphocytes in sinusoids. Necrotizing hepatocytes were observed sporadically. The ultrastructural changes included swollen mitochondria with injured cristae, dilated cisternae of rough endoplasmic reticulum, and damaged intercellular contacts between hepatocytes. In the Cd/Zn group, Zn was not able to completely protect the liver, but the changes were less pronounced. The specific activity of superoxide dismutase was significantly increased in the Cd group. Glutathione peroxidase was significantly increased in all experimental groups. In the Cd/Zn group, zinc co-administration had a protective effect on the activity of antioxidant enzymes. Exposure of turkeys to cadmium did not affect the content of TBARS in the liver.

Morphological Changes in the Liver and the Response of Antioxidant Enzymes after Turkeys' Chronic Exposure to Cadmium

Objective of this study was to investigate changes in biological activity of blood leukocytes in Japanese quails, caused by zinc and cadmium administration. Four groups of Japanese quails were used. Three experimental groups of quails were exposed either to Cd (0.12 mg Cd/quail), Zn (4 mg Zn/quail) or a combination of Cd and Zn (0.12 mg Cd, 4 mg Zn/quail), which were added daily to the drinking water. The fourth group was the control group. The metabolic activity of phagocytes and mitogenic activation of lymphocytes to phytohemaglutinine (PHA) were determined on day 37, 58 and 118 of exposure. The numbers of peripheral blood leukocytes of Japanese quail after cadmium and zinc addition in all groups of birds were without significant differences, however, the functional activities of phagocytes and lymphocytes in the Cd-group of quails were significantly decreased. The metabolic activity of phagocytes decreased significantly at all time points analysed (P < 0.05-0.001) in comparison to the control group and the Cd-Zn group. Similarly, the response of lymphocytes to PHA activation in the Cd exposed group of quails decreased significantly on day 58 and 118 of exposure when compared to the control group (P < 0.05) and Zn-group of quails (P < 0.01). Zn in combination with Cd eliminated the immunotoxic effect of Cd on metabolic activity of phagocytes and improved lymphocyte answer to PHA, when compared to the Cd-group on day 58 and 118 of metal administration. The results of the present study indicate that cadmium caused a significant decrease of metabolic activity of phagocytes and mitogenic activation of lymphocytes in peripheral blood of Japanese quails. Simultaneous administration of Zn and Cd eliminated the immunotoxic effect of Cd on functional activity of phagocytes and lymphocytes, and zinc improved both investigated functional parameters of immune cells.

L'ubomír Bindas

Papers

Effect of oral cadmium and zinc application on leukocytes biological activity in Japanese quails (Coturnix coturnix japonica)