Background and aim: The increasing spread of heavy metals in human life has become a concern. Environmental pollutants, including aluminum, are harmful to human health and lead to nervous system disorders. On the other hand, our country is facing middle age and knowing the factors affecting age-related diseases is very valuable. In this study, the effect of Lactobacillus acidophilus probiotic on memory performance in male rats treated with streptozotocin and aluminum chloride was investigated. 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, passive avoidance memory, novel object recognition test and motor activity were evaluated. Results: In passive avoidance test and novel object recognition test, treatment with streptozotocin and aluminum chloride alone and toghether, significantly reduced memory recall compared to the control group (P<0.001). In these groups, treatment with probiotics significantly improved memory to the level of the control group (P<0.001). Examination of motor activity did not show any significant difference between experimental groups (P>0.05). Conclusion: This research shows that the use of probiotic Lactobacillus acidophilus is able to prevent memory destruction caused by streptozotocin and aluminum chloride each alone or together. In this way, the use of probiotics in the diet is recommended.
