Neuroprotective effects of
melatonin against
free radical damage have been studied extensively. Thinner containing 60-70%
toluene is a neurotoxic mixture which is widely used as an aromatic industrial
solvent. This product has been shown to cause functional and structural changes in the central nervous system.
Toluene generates
reactive oxygen species (ROS) and the toxic effects relating to these reactants. In the present study we investigated glial reactivity in hippocampus, cortex and cerebellum and the expression of
glial fibrillary acidic protein (GFAP) after exposure of rats to
toluene vapor (3000 ppm) for 45 days. We also examined the protective effects of
melatonin against
gliosis. Western blots demonstrated a marked elevation in total GFAP, a specific marker for astrocytes, by thinner fume inhalation in the hippocampus (P<0.001), cortex (P<0.01) and cerebellum (P<0.05) of rats.
Melatonin administration prevented the increase of total GFAP induced by thinner fume inhalation. Thinner exposure caused a significant increase of lipid peroxidation products (
malondialdehyde and 4-hydroxyalkenals) in all brain regions (P<0.01 for each region), and this elevation was also was inhibited by
melatonin. Furthermore,
melatonin augmented
glutathione levels in all brain regions (P<0.05 for each region) investigated. In conclusion,
melatonin treatment may provide neuroprotection against
toluene neurotoxicity by increasing the survival of glial cells possibly by directly scavenging ROS and by indirectly augmenting their
antioxidant capacity.