Electrophysiological and biochemical response in rats on intratracheal instillation of manganese

Abstract

Chronic exposure to excess manganese via inhalation of metal fumes causes central nervous system damage. For modelling Mn aerosol inhalation, male Wistar rats were intratracheally instilled with MnCl2 solution (0.5 mg/kg b.w. MnCl2; n=12) 5 days a week for 5 weeks. At the end of the treatment, somatosensory cortical evoked potentials, elicited by double-pulse stimulation, were recorded from the animals in urethane anaesthesia. Body weight gain, organ weights, and Mn level in brain, lung and blood samples were also measured. In brain samples, gene expression level of MnSOD (Mn superoxide dismutase) was determined. The effect of Mn was mainly seen on the evoked potential amplitudes, and on the second:first ratio of these. Tissue Mn concentration was elevated in brain and lungs, but changed hardly in the blood. Relative weight of heart, thymus, lungs and brain was significantly altered. The level of MnSOD transcript in brain tissue decreased. The observed effects showed that Mn had access to the brain and that somatosensory cortical responses evoked by double-pulse stimulation might be suitable biomarkers of Mn intoxication.

Size-Dependent Toxicity Differences of Intratracheally Instilled Manganese Oxide Nanoparticles: Conclusions of a Subacute Animal Experiment

“…Based on the health importance of human exposure to airborne Mn-containing NPs, the need for neurotoxicological assessment of MnO 2 NPs (stressed by Li et al [9]), and on our previous experience with modeling such exposure in rats [29][30][31], the aim of the present study was to investigate the effect of particle size, within the nano range, on the general and nervous system toxicity of MnO 2 NPs in subacutely treated rats.…”

Neurotoxic effects of subchronic intratracheal Mn nanoparticle exposure alone and in combination with other welding fume metals in rats

“…Previous own studies on the neurotoxicity of Mn revealed, as the main electrophysiological alteration in rats, a latency lengthening of cortical sensory EPs, observed after several weeks of Mn exposure by the oral route (dissolved MnCl2: Vezér et al 2005) or by intratracheal application of dissolved (Máté et al 2011) or nanoparticulate Mn (MnO2 nanoparticles (NPs): Oszlánczi et al 2010). Parallel shift of the spontaneous cortical activity to higher frequencies was also observed.…”