Concentrations of some essential elements in the brain of aluminum-exposed rats in relation to the age of exposure

Trace metal imbalance associated with oxidative stress and inflammatory status in anti-hepatitis C virus antibody positive subjects

Toxic and essential trace metals, oxidative stress, and inflammatory status were evaluated in anti-hepatitis C virus (HCV) antibody-positive subjects. Blood biochemical parameters were determined in anti-HCV antibody-positive (n=17) and -negative controls (n=46). Compared with controls, anti-HCV antibody-positive individuals had significantly lower concentrations of plasma zinc (Zn); higher copper (Cu), iron (Fe), lead (Pb), cadmium (Cd), and aluminum (Al); and lower activities of erythrocyte antioxidant enzymes glutathione peroxidase and catalase, and elevated superoxide dismutase. Significantly increased lipid peroxidation malondialdehyde (MDA), and inflammatory markers such as alanine aminotransferase (ALT), high sensitivity C-reactive protein (hs-CRP), ferritin, and Cu/Zn ratios, as well as decreased albumin and high density lipoprotein (HDL) concentrations were observed. We have found significant interactions between toxic (e.g., Pb, Cd, and Al) and essential metals (e.g., Zn, Cu, Fe), which correlated with MDA. In conclusion, anti-HCV antibody-positive subjects had abnormal distributions of trace metals that may aggravate oxidative stress and inflammation, and exacerbate hepatic damage.

Influence of age on aluminum-induced neurobehavioral effects and morphological changes in rat brain

Aluminum (Al) is potentially toxic for mammals. In contrast to well documented Al neurotoxicity, neurobehavioral studies of Al in rodents have generally not produced robust or consistent results. In the present study, 16 young male (21 days old) and 16 old male (18 months) rats were exposed to 0 (control group) and 100 mg/kg/day of Al administered as Al nitrate nonahydrate in drinking water concurrently with citric acid (356 mg/kg/day) for a period of 100 days. At the end of the exposure period, rats were evaluated for motor activity in an open-field apparatus and learning in a passive avoidance test. After behavioral testing, rats were sacrificed and brain samples were collected to determine Al concentrations and to study synapses in the left CA1 fields of hippocampal formation. While no significant effects of Al exposure between groups could be detected on behavior, the total number of synapses decreased with age and Al exposure. In turn, the percentage of perforated synapses significantly increased in old Al-loaded rats.

Ultrastructural study of rat hippocampus after chronic administration of aluminum L-glutamate: an acceleration of the aging process

An ultrastructural study of rat hippocampus was performed on young (group 1) and old (group 4) rats receiving daily subcutaneous injections of aluminum L-glutamate and on old untreated rats (group 5). Young controls were treated with sodium L-glutamate (group 2) and physiological saline (group 3). Group 1 showed vacuolated astrocytes with numerous lipofuscin deposits, mitochondrial swelling, a thinning of the myelin sheath, and many multivesicular bodies invading the cytoplasm. Cellular structure did not appear to be affected in groups 2 and 3. Group 4 showed swollen mitochondria, a demyelination process in axonal regions, sizable perivascular oedema with vessel retraction and gliofilament bundles. In this group, lipofuscin deposits in astrocytes were associated with multivesicular bodies that thinned the myelin sheath to the breaking point; however, no excitotoxic glutamate-induced effects were observed. In group 5, extreme cytoplasmic vacuolation was observed, with massive mitochondrial swelling, considerable thinning of the myelin sheath (at times to the breaking point), sizable vacuolar degeneration and gliofilament bundles. These results indicate that ultrastructural alterations in the hippocampus, such as cell vacuolization, massive mitochondrial swelling and the demyelination process, occur with aging and independently of aluminum intoxication. Similar alterations were observed in aluminum L-glutamate-intoxicated young rats, but not in controls. These results are consistent with aluminum-induced acceleration of the aging process.