Depletion of liver glutathione levels in rats: a potential confound of nose-only inhalation

l-Cysteine augments microtubule-associated protein 2 levels and enhances antioxidant activity in rats following traumatic brain injury

l-Cysteine is a well-known sulfur-containing non-essential amino acid that can be oxidized to cysteine, which possesses a variety of pharmacological actions, including antioxidant and anti-inflammatory activities. Traumatic brain injury (TBI) is defined as a closed head injury that leads to temporary alterations in neural function and further leads to pathophysiological processes. In the present study, rats were categorized into sham, control, 100 mg/kg l-cysteine, and 200 mg/kg l-cysteine groups and then the levels of lipid peroxidation, reduced glutathione (GSH), catalase, superoxide dismutase (SOD), reactive oxygen species (ROS), and mRNA and protein expression of microtubule-associated protein 2 (MAP2) were determined. Following supplementation with l-cysteine, there were reductions in lipid peroxidation and ROS levels, whereas catalase, SOD, and GSH levels increased. Additionally, the mRNA expression of MAP2 in the control rats was drastically reduced by 67% compared to the sham rats. However, supplementation with 100 mg/kg of l-cysteine and 200 mg/kg of l-cysteine significantly increased MAP2 mRNA expression by 84.8% and 169.7%, respectively. Similarly, MAP2 protein expression was drastically reduced by 61% in control rats compared to sham rats, but supplementation with 100 mg/kg of l-cysteine and 200 mg/kg of l-cysteine significantly increased MAP2 protein expression by 41% and 94.9%, respectively. Taken together, these data suggest that supplementation with l-cysteine significantly reduced lipid peroxidation and ROS levels, but increased antioxidant levels and the mRNA and protein expression of MAP2 in rats following TBI.

Quantification of short and long asbestos fibers to assess asbestos exposure: a review of fiber size toxicity

The fibrogenicity and carcinogenicity of asbestos fibers are dependent on several fiber parameters including fiber dimensions. Based on the WHO (World Health Organization) definition, the current regulations focalise on long asbestos fibers (LAF) (Length: L ≥ 5 μm, Diameter: D < 3 μm and L/D ratio > 3). However air samples contain short asbestos fibers (SAF) (L < 5 μm). In a recent study we found that several air samples collected in buildings with asbestos containing materials (ACM) were composed only of SAF, sometimes in a concentration of ≥10 fibers.L-1. This exhaustive review focuses on available information from peer-review publications on the size-dependent pathogenetic effects of asbestos fibers reported in experimental in vivo and in vitro studies. In the literature, the findings that SAF are less pathogenic than LAF are based on experiments where a cut-off of 5 μm was generally made to differentiate short from long asbestos fibers. Nevertheless, the value of 5 μm as the limit for length is not based on scientific evidence, but is a limit for comparative analyses. From this review, it is clear that the pathogenicity of SAF cannot be completely ruled out, especially in high exposure situations. Therefore, the presence of SAF in air samples appears as an indicator of the degradation of ACM and inclusion of their systematic search should be considered in the regulation. Measurement of these fibers in air samples will then make it possible to identify pollution and anticipate health risk.

Protective effect of salicylic acid on Hg(0) intoxication in mice

Elemental mercury (Hg(0)) is a hazardous metal with significant human exposure through diverse sources. In this study, the role of salicylic acid (SA) was assessed against Hg(0)-induced injury in mice, with the aim of screening alternative clinical drugs to prevent or treat Hg(0) poisoning. An exposure to Hg(0) (1.0 mg/m(3) in a glass box) for 2 h per day for successive 15 d significantly increased Hg accumulation in mouse brain and lung, inhibited the animal growth and altered the neurobehavior such as impairing the spatial learning and memory in the Barnes maze test. However, although oral SA (5.5 mg/kg body weight) during the Hg(0) exposure did not reduce the Hg levels in these organs, it effectively counteracted the Hg(0)-induced growth inhibition, and improved the behavioral performance, accompanied by a series of ameliorations in the antioxidative defense and anti-inflammatory response. For instance, when compared with control, Hg(0)-inhaled animals had significant decreases in the activities of superoxide dismutase and peroxidase, and in the levels of reduced form of glutathione and the ratio to its oxidized form, concomitantly with a high accumulation of hydrogen peroxide and malondialdehyde in the brain and lung. However, these values in Hg(0) + SA-exposed animals were comparable with the basal levels in control. Likewise, interleukin-6 in the brain and lung of Hg(0)-exposed animals were dramatically elevated, whereas it was maintained to the basal level in Hg(0) + SA-exposed animals. These data suggested that application of SA could protect mice against Hg(0)-induced injury.