The short-term oxidative damage demonstrated here could participate in the development of central nervous system symptoms during sepsis development, or even septic encephalopathy. The alterations in the superoxide dismutase/catalase relation were temporally related to the occurrence or not of oxidative damage in the central nervous system.

No abstract

Malathion is a pesticide with high potential for human exposure. However, it is possible that during the malathion metabolism, there is generation of reactive oxygen species (ROS) and malathion may produce oxidative stress in intoxicated rats. The present study was therefore undertaken to determine malathion-induced lipid peroxidation (LPO), protein carbonylation and to determine whether malathion intoxication alters the antioxidant system in brain rats. Malathion was administered intraperitoneally in the acute and chronic protocols in the doses of 25, 50, 100 and 150 mg malathion/kg. The results showed that LPO in brain increased in both protocols. The increased oxidative stress resulted in an increased in the activity of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT), observed in cortex, striatum in the acute malathion protocol and hippocampus in the chronic malathion protocol. Our results demonstrated that malathion induced oxidative stress and modulated SOD and CAT activity in selective brain regions.

There is no description on the mechanisms associated with blood-brain barrier (BBB) disruption during sepsis development. Thus, we here determined changes in permeability of the BBB in an animal model of severe sepsis and the role of matrix metalloproteinase (MMP)-2 and MMP-9 in the dysfunction of the BBB. Sepsis was induced in Wistar rats by cecal ligation and perforation. BBB permeability was assessed using the Evans blue dye method. The content of MMP-2 and MMP-9 in the cerebral microvessels was determined by western blot. The activity of MMP-2 and MMP-9 was determined using zymography. An inhibitor of MMP-2 and MMP-9 or specific inhibitors of MMP-2 or MMP-9 were administered to define the role of MMPs on BBB permeability, brain inflammatory response, and sepsis-induced cognitive alterations. The increase of BBB permeability is time-related to the increase of MMP-9 and MMP-2 in the microvessels, both in cortex and hippocampus. Using an MMP-2 and MMP-9 inhibitor, or specific MMP-2 or MMP-9 inhibitors, the increase in the permeability of the BBB was reversed. This was associated with lower brain levels of interleukin (IL)-6 and lower oxidative damage. In contrast, only the inhibition of both MMP-9 and MMP-2 was able to improve acute cognitive alterations associated with sepsis. In conclusion, MMP-2 and MMP-9 activation seems to be a major step in BBB dysfunction, but BBB dysfunction seems not to be associated with acute cognitive dysfunction during sepsis development.

Our data provide the first experimental demonstration that survivors from CLP show learning and memory impairment after complete physical recovery from sepsis.