Influence of zinc on the biokinetics of (65)Zn in brain and whole body and its bio-distribution in aluminium-intoxicated rats

Homeostatic changes of some trace elements in geriatric rats in the condition of oxidative stress induced by aluminum and the beneficial role of resveratrol

BACKGROUND

Elderly individuals are exposed to trace element imbalances due to the reduced capacity of their organism to utilize minerals in a direct relationship with many circumstances.

OBJECTIVES AND METHODS

The aim of this study was to assess the protective role of resveratrol upon the homeostatic changes of some trace elements in geriatric rats in the condition of oxidative stress induced by aluminum exposure. Forty Wistar rats, 18-20 months old, were divided randomly into four groups (n = 10): control (C) - receiving 1 ml of physiologically saline (P.S.) via intraperitoneal (i.p) administration, E1 - 1 ml of P.S. and 1000 ppb aluminum sulphate (AS) in drinking water ad libitum, E2 - 20 mg/kg^-1 resveratrol, i.p. and 1000 ppb AS in drinking water, E3 - 20 mg/kg^-1 resveratrol i.p. The groups C and E3 received distilled water as drinking water ad libitum. The i.p administrations were once a week for four weeks period. The levels of oxidative stress marker's were analyzed (glutathione, glutathione' peroxidase, superoxide dismutase, and catalase) of the proteins' (total protein, albumin, and hemoglobin) in serum and also the levels of the main trace elements (copper, zinc, iron, selenium, manganese and magnesium) in blood, liver, kidney and spleen.

RESULTS

Significant decrease (p < 0.05) of total protein (TP), albumin (ALB), catalase (CAT), increase significant (p < 0.05) of glutathione reductase (GSH-r), glutathione peroxidase (GPx) and superoxide dismutase (SOD) in E1 groups, compared with control, E2, and E3 groups was ascertained. There were also observed significant (p < 0.05) decreases in Cu, Zn, Fe and Mg, not significant (p > 0.05) increase of Se and Mn in blood, significant (p < 0.01) increase of Cu, Zn, Mg, Se, Mn in kidney and liver and Fe, in spleen of geriatric rats from E1 group compared to the control group. Insignificant differences (p > 0.05) were recorded in groups which received resveratrol (E2 and E3) compared to the control group, but significant differences (p < 0.05), especially in blood and liver samples, compared to E1.

CONCLUSIONS

The results suggest that resveratrol can prevent the homeostatic imbalance of trace elements in geriatric rats in the condition of oxidative stress induced by aluminum exposure.

Modulation of (14) C-labeled glucose metabolism by zinc during aluminium induced neurodegeneration

Aluminium (Al) is one of the most prominent metals in the environment and is responsible for causing several neurological disorders, including Alzheimer's disease. On the other hand, zinc (Zn) is an essential micronutrient that is involved in regulating brain development and function. The present study investigates the protective potential of Zn in the uptake of (14) C-labeled amino acids and glucose and their turnover in rat brain slices during Al intoxication. Male Sprague Dawley rats (140-160 g) were divided into four different groups: normal control, Al treated (100 mg/kg body weight/day via oral gavage), Zn treated (227 mg/liter in drinking water), and Al + Zn treated. Radiorespirometric assay revealed an increase in glucose turnover after Al exposure that was attenuated after Zn treatment. Furthermore, the uptake of (14) C-labeled glucose was increased after Al treatment but was appreciably decreased upon Zn supplementation. In addition, the uptakes of (14) C-lysine, (14) C-leucine, and (14) C-aspartic acid were also found to be elevated following Al exposure but were decreased after Zn treatment. Al treatment also caused alterations in the neurohistoarchitecture of the brain, which were improved after Zn coadministration. Therefore, the present study suggests that Zn provides protection against Al-induced neurotoxicity by regulating glucose and amino acid uptake in rats, indicating that Zn could be a potential candidate for the treatment of various neurodegenerative disorders.