Thymic cytoarchitecture changes in mice exposed to vanadium

Abstract

The thymus is a vital immune system organ wherein selection of T-lymphocytes occurs in a process regulated by dendritic and epithelial thymic cells. Previously, we have reported that in a mouse model of vanadium inhalation, a decrease in CD11c dendritic cells was observed. In the present study, we report on a thymic cortex-medulla distribution distortion in these hosts due to apparent effects of the inhaled vanadium on cytokeratin-5 (K5 þ ) epithelial cells in the same mouse model -after 1, 2, and 4 weeks of exposure -by immunohistochemistry. These cells -together with dendritic cells -eliminate autoreactive T-cell clones and regulate the production of regulatory T-cells in situ. Because both cell types are involved in the negative selection of autoreactive clones, a potential for an increase in development of autoimmune conditions could be a possible consequence among individuals who might be exposed often to vanadium in air pollution, including dwellers of highly polluted cities with elevated levels of particulate matter onto which vanadium is often adsorbed. ARTICLE HISTORY

Protective Effects of Dietary Antioxidants against Vanadium-Induced Toxicity: A Review

“…A suicidal death after ingestion of an undetermined amount of ammonium vanadate has also been reported [29]. In addition, laboratory-based studies conducted in animal models or cell cultures found that vanadium exposure can induce a variety of toxic effects such as cardiovascular effects (e.g., vascular endothelial dysfunction [30] and arterial hypertension [31]), immune toxicity (e.g., damage to the spleen [32] and thymus [33]), neurotoxicity (e.g., hippocampal alterations [34] and memory loss [35]), developmental disturbances (e.g., increased embryolethality and skeletal defects [36]), and pulmonary toxicity [37]. It should be added that, besides the dose of vanadium and the route of vanadium exposure, many other factors such as the form of vanadium (inorganic versus organic forms) and interactions with other elements such as selenium [38,39] or magnesium [40] can also influence vanadium toxicity (depicted in Figure 1).…”

The Effect of Atmospheric Pollution on the Thymus

“…The density mean showed the changes in the presence of K5+, ocher-stain cells that increased during the first week of exposure compared with controls; however, the stain density at weeks 2 and 4 had a slight decrease but never reached the control values p < 0.05. These results showed that V produced changes in thymus cytoarchitecture, in addition of an increase in K5+ cells, changes that suggest that the T-cell selection was disrupted by V-inhalation [5]. Also, the presence of nitrosative stress as possible explanation of our findings was explored with 3-nitrotyrosine (3-NT) [38].…”

“…One of the systems affected by PM is the lymphoid. Few papers report the direct effect of the PM in the Thymus, which is a central actor in the future definition of the immune response and self-recognition and self-tolerance, increasing the risk for developing allergic or autoimmune diseases [2][3][4][5][6].…”

Toxic Effects of Inhaled Vanadium Attached to Particulate Matter: A Literature Review

“…The cTEC cells positively select T lymphocytes that strongly recognize major histocompatibility complex (MHC) molecules. At the end of the maturation process, the T lymphocytes leaving the thymus will be a CD4+ helper or CD8+ cytotoxic [53,54].…”