Comparison of neurobehavioral and biochemical effects in rats exposed to dusts from copper smelter plant at different locations

Abstract

Mixed exposure to metals (including arsenic and lead) associated with the neurological and respiratory effects constitute one of the major health problems of copper smelting. Chemical composition of the dust, and the expected health effect of inhalation can be very diverse at different parts of the smelter plant. The aims of this study were to compare lung responses and behavioral effects in female Wistar rats after instillation of dust collected from different production processes at the same smelter department. Dusts collected at two different locations of furnace hall were sifted through 25-μm-mesh sieve. Obtained dust fractions, P-25(I) collected near stove, rich in heavy metals and arsenic, and P-25(II) collected near anode residue storage site, rich in aluminium, were instilled to rats. At 1, 7 and 30 days after dusts instillation, lung injury and inflammation were measured by analyzing sings of lung permeability in the bronchoalveolar lavage fluid (BALF), cell differentiation in BALF sediment and lung morphology. The behavioral studies were done 30 days after exposure. Results of biochemical tests showed a strong pro-inflammatory effect of P-25(I) fractions. Mostly characteristic effects after instillation of P-25(I) samples were 10× increased protein leakages in BALF. Both P-25(I) and P-25(II) fractions caused a reduction of Clara-cell 16 protein concentration (CC16) in BALF and activation of serum butyrylcholinesterase (BChE) at all time points. The morphological studies after exposure to P-25(I) fractions showed multi-focal infiltrations in the alveoli. The behavioral results, especially P-25(II) group rats (in open filed, passive avoidance and hot plate tests), indicated adverse effects in the nervous system, which may be related to changes in the dopaminergic and cholinergic pathway. The symptoms were noted in the form of persistent neurobehavioral changes which might be associated with the content of neurotoxic metals. e.g. Al, Mn and/or As. Decrease of CC16 concentration that occurred immediately after instillation of both dust samples, point out impaired anti-inflammatory potential, resulted in early harmful effect not only to the respiratory tract but also to the whole body, including the nervous system.