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Introduction: It has been found that exposure to ambient air pollution, such as particulate matter (PM), results in cognitive impairments and mental disorders. This study aimed to investigate the possible neuroprotective effects of curcumin, a polyphenol compound, on the neurobehavioral deficits and to identify the role of oxidative stress in dusty PM exposure rats. Methods and Materials: Rats received curcumin (50 mg/kg, daily, gavage, 2 weeks) 30 min before placing in a clean air chamber (≤ 150 µg/ m3, 60 min daily, 2 weeks) or ambient dusty PM chamber (2000–8000 µg/m3, 60 min daily, 2 weeks). Subsequently, the cognitive and non-cognitive functions of the animals were evaluated using standard behavioral tests. Moreover, blood–brain barrier (BBB) permeability, brain water content (BWC), oxidative antioxidative status, and histological changes were determined in the cerebral cortex and hippocampal areas of the rats . Results: Our results showed that curcumin administration in dusty PM exposure rats attenuates memory impairment, decreases anxiety/depression-like behaviors, and improves locomotor/exploratory activities. These findings were accompanied by reduced BBB permeability and BWC, decreasing oxidative stress and neuronal loss in the cerebral cortex and different hippocampal areas. Conclusion: The results of this study suggest that curcumin antioxidant properties may contribute to its efficacy in improving neurological deficits and preventing neuronal loss associated with dusty PM exposure. [ABSTRACT FROM AUTHOR]

Introduction: Alzheimer's disease is accompanied by an abnormal high accumulation of cis-P tau. In the present study, the changes in synaptic plasticity and synaptic currents in hippocampal dorsal and ventral regions following tau accumulation (tauopathy) were investigated. Cis-P tau was microinjected into the dorsal hippocampus to generate Alzheimer’s like-disease model in C57BL/6 mice. Cis-P tau injected animals showed a significant impairment in learning and memory in Y-maze and Barnes maze tests. In another group of animals, the generation of long-term potentiation (LTP) was evaluated in hippocampal slices seven months after cis-P tau injection. LTP induction was disrupted only in the dorsal but not ventral hippocampal slices. The basal synaptic transmission was also reduced in dorsal hippocampal slices. In addition, hippocampal sampling was done, and the number of cells was assessed by Nissl staining. The decrement of cell number was higher in the dorsal compared to the ventral hippocampus. Tauopathy increased the glutamatergic, but not GABAergic currents, in dorsal hippocampus and thereafter, increased the excitation to inhibition ratio in this area. While, no changes occurred in synaptic currents in ventral hippocampus. Intra-hippocampal cis-P tau injection produced learning and memory impairment. This impairment might result from LTP disruption, a significant decrease in the number of neurons in the dorsal hippocampus and the increase in excitation to inhibition ratio in this area. [ABSTRACT FROM AUTHOR]

Introduction: Peppers have been used in traditional medicine for a long time and its major component, piperine (PPR), has exhibited antioxidant, anticancer, anti-inflammatory, antihypertensive, hepatoprotective, and neuroprotective properties. The purpose of this study was to investigate the effects of piperine on cognitive impairment in adult male rats after inducing traumatic brain injury (TBI). Methods and Materials: Spatial learning and memory of rats were assessed by Morris Water Maze during a 5-day training period. After 24 hours, rats were randomly assigned to control, sham, TBI, and PPR groups. Rats of PPR groups received PPR (50mg/kg, dissolved in sesame oil; oral gavage), 30 min after TBI induction and then every 24 hours for seven days. The parameters of escape latency, target quadrant duration, traveled distance, and swimming velocity were measured. Results: TBI impaired memory acquisition on 8 days post-injury, verified by an increase in the latency to the first platform and a decrease in target quadrant duration in the Morris water maze test. PPR oral administration post-injury attenuated the deteriorative effect of TBI on memory. Conclusion: Our data show that piperine treatment after brain injury can inhibit cognitive impairment induced by TBI which may make it an effective therapeutic target in post-injury complications. [ABSTRACT FROM AUTHOR]

Introduction: Gut bacteria are known to have a significant impact on physiological processes in many organs of the body. Specifically, the gut microbiota profoundly affects nervous system development and function through bidirectional communication called the gut-microbiota-brain axis. As a medial part of the temporal lobe, the hippocampus is known to be involved in cognition, emotion, and anxiety. There is increasing evidence that the hippocampus is a target of the gut microbiota. We conducted a systematic review linking the hippocampus with gut microbiota and probiotics. Search Method: All experimental and clinical studies published by 2023 have been reviewed. In this review, the effects of gut microbiota on behavioral, electrophysiological, biochemical, and histological aspects of the hippocampus were evaluated. Results: The impact of gut microbiota disruption and probiotic supplementation on the microbiota-hippocampal connection has also been considered. Studies show that a healthy gut microbiota is required for normal hippocampal-dependent learning, memory, and synaptic plasticity. Currently known mechanisms include the production and regulation of neurotrophins, neurotransmitters, and receptors, regulation of intracellular molecular processes, normalization of pro-inflammatory/anti-inflammatory and oxidative/antioxidant factors, and hippocampal histological stability. Studies have also shown that hippocampal neural circuit activity and hippocampal behavioral function respond positively to different mixtures of probiotic bacteria. Conclusion: A growing number of evidence from animal studies point to a close relationship between the hippocampus, gut microbiota, and probiotic bacteria. However, few human or clinical studies have confirmed such associations. Most of the research on this subject has been published in the last four years, so future intensive research is pending. [ABSTRACT FROM AUTHOR]