Background and aim: Heavy metals, including aluminum, are potentially harmful to human health and the environment. One of the severe effects of aluminum metal is the effect on the brain and memory impairment. Alzheimer's disease is the most common neurodegenerative disease that is associated with memory and cognition disorders, and the risk of it increases with age. Our country is facing middle age and it is very important to know the factors affecting age-related diseases. The present study has investigated the effect of Lactobacillus acidophilus probiotic on the accumulation of aluminum chloride in blood and brain tissue, as well as the oxidative stress caused by streptozotocin and aluminum chloride, either alone or simultaneously. Materials and Methods: In this experimental study, adult male Wistar rats were divided into seven groups: control, streptozotocin (3 mg/kg) alone and with probiotic, aluminum chloride (0.8 g/L) alone and with probiotic, streptozotocin and aluminum chloride alone and with probiotics. In all experimental groups, cannulation was performed in the lateral ventricles. Animals received intracerebral injection of saline or streptozotocin on the first and third days after cannulation. Treatment with aluminum chloride and probiotics (with certain amount of turbidity) dissolved in drinking water was done from 1 day before cannulation until the beginning of experiments. At the end of the treatment Blood sampling was done from the right ventricle of the heart. Then, the level of malondialdehyde, total antioxidant power, activity level of superoxide dismutase and catalase enzymes in blood serum were measured. Aluminum levels were also measured in blood serum and brain tissue. Statistical analyzes were performed by SPSS software and the significance level was considered p<0.05. Results: In animals that used drinking water containing aluminum chloride, the level of this pollutant in blood serum (p<0.001) and brain tissue (p<0.001) increased significantly compared to other groups. Also, drinking water containing aluminum chloride and intracerebral injection of streptozotocin each alone and simultaneously led to a significant decrease in total antioxidant power (p<0.001), superoxide dismutase and catalase enzyme levels (p<0.001). And a significant increase in the level of malondialdehyde (p>0.001) was observed in the blood serum compared to the control group. While in all groups, the treatment of animals with Lactobacillus acidophilus probiotic leads to the reduction of aluminum chloride in the blood serum and brain tissue, as well as the improvement of oxidative stress factors to the level of the control group. Conclusion: This research showed that aluminum chloride through drinking water is able to accumulate in the brain tissue and cause oxidative stress. The use of Lactobacillus acidophilus probiotic prevents the accumulation of aluminum chloride in the blood and brain tissue. Also, this probiotic is able to prevent oxidative stress caused by streptozotocin alone or together with aluminum chloride, so it is recommended to use probiotics in the diet.
