Long-term effects of chromium on morphological and immunological parameters of Wistar rats.

Hexavalent chromium raises high concern because of its wide industrial applications and reported toxicity. Long-term (135 days) oral exposure of Wistar rats to chromium in the form of K2Cr2O7 (exposed group~20 mg/kg/day) led to a decrease in thymus mass and thymocytes' number and caused structural and functional changes in the lymph nodes and spleen, namely lymphoreticular hyperplasia and plasmocytic macrophage transformation. Programmed cell death was increased in both thymocytes and splenocytes and decreased in lymphocytes in the T-zones of spleen and lymph nodes. Moreover, Cr (VI) administration decreased myeloid cells' and neutrophils' number, while it increased lymphoid and erythroid cells' number in bone marrow. Cr (VI) immune system effects seem to be related to oxidative stress induction, as depicted by the increased levels of diene conjugates and malondialdehyde in the spleen and liver and by the decreased activity of catalase and superoxide dismutase in rats' erythrocytes. In addition, exposure to Cr (VI) decreased copper, nickel and iron concentrations in blood and liver, while Cr levels in blood, spleen and liver were increased, as expected. The observed changes in the series of immunological parameters studied contribute to the development of new approaches for the prevention of low level Cr exposure toxicity.

[Experimental evaluation of the impact of low doses of the herbicide 2,4-D in drinking water on some indices of lipid and immune status].

There were studied features of the manifestation of incoming with potable water nontoxic doses of the herbicide 2,4-D on the body mass index, some indices of lipid metabolism and immune system in different types of diets in the experiment in rats. There was shown a significant gain in body weight of animals, and MDA and leptin level in the serum under the action of a herbicide in conjunction with a high-calorie diet. In all experimental groups there was noted the increased level of total cholesterol, tendency to the increase of LDL cholesterol. Under the action of the herbicide there was noted an increase of IL-6, TNF-a and the numbers of leukocytes and, on the contrary, the reduction of the number of thymocytes and kariocytes in thymus and spleen.