The Effect of Physical Exercise Pretreatment on Spatial Memory and Learning and Function of Mitochondria in the Brain in Type 2 Diabetic Rats.

Background: The prevalence of type 2 diabetes mellitus (T2DM) is increasing worldwide, and this issue is one of the major concerns in the pending years. T2DM causes numerous complications, including cognition, learning, and memory impairments. The positive effect of physical exercise as a popular approach has been shown in many chronic diseases. Further, the improvement effects of exercise on cognition and memory impairment have been noticed. Objectives: This study examines the possible preventative effects of physical exercise on spatial memory attenuation and brain mitochondrial dysfunction caused by T2DM. Methods: Male Wistar rats received treadmill exercise (30 min per day, five days per week for two or four weeks). Then, T2DM was induced by a high-fat diet and an injection of streptozotocin (30 mg/kg). Spatial learning and memory were assessed by the Morris water maze test. Further, brain mitochondrial function, including reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), mitochondrial swelling, outer membrane damage, cytochrome c release, and ADP/ATP ratio, were measured. Results: Impaired spatial memory in T2DM rats was observed. Furthermore, brain mitochondrial dysfunction was demonstrated proved by increased ROS generation, MMP collapse, mitochondrial swelling, outer membrane damage, cytochrome c release, and ADP/ATP ratio. Conversely, physical exercise, before diabetes onset, significantly ameliorated spatial memory impairment and brain mitochondrial dysfunction. Conclusions: This study reveals that physical exercise could prevent diabetes-induced spatial memory impairment. Moreover, it could ameliorate brain mitochondrial dysfunction as one of the possible underlying mechanisms of spatial memory impairment in T2DM.

Alpha pyrrolidinovalerophenone (α-PVP) administration impairs spatial learning and memory in rats through brain mitochondrial dysfunction.

Novel psychoactive substances (NPS) consumption has increased in recent years, thus NPS-induced cognitive decline is a current source of concern. Alpha-pyrrolidinovalerophenone (α-PVP), as a member of NPS, is consumed throughout regions like Washington, D.C., Eastern Europe, and Central Asia. Mitochondrial dysfunction plays an essential role in NPS-induced cognitive impairment. Meanwhile, no investigations have been conducted regarding the α-PVP impact on spatial learning/memory and associated mechanisms. Consequently, our study investigated the α-PVP effect on spatial learning/memory and brain mitochondrial function. Wistar rats received different α-PVP doses (5, 10, and 20 mg/kg) intraperitoneally for 10 sequential days; 24 h after the last dose, spatial learning/memory was evaluated by the Morris Water Maze (MWM). Furthermore, brain mitochondrial protein yield and mitochondrial function variables (Mitochondrial swelling, succinate dehydrogenase (SDH) activity, lipid peroxidation, Mitochondrial Membrane Potential (MMP), Reactive oxygen species (ROS) level, brain ADP/ATP proportion, cytochrome c release, Mitochondrial Outer Membrane (MOM) damage) were examined. α-PVP higher dose (20 mg/kg) significantly impaired spatial learning/memory, mitochondrial protein yield, and brain mitochondrial function (caused reduced SDH activity, increased mitochondrial swelling, elevated ROS generation, increased lipid peroxidation, collapsed MMP, increased cytochrome c release, elevated brain ADP/ATP proportion, and MOM damage). Moreover, the lower dose of α-PVP (5 mg/kg) did not alter spatial learning/memory and brain mitochondrial function. These findings provide the first evidence regarding impaired spatial learning/memory following repeated administration of α-PVP and the possible role of brain mitochondrial dysfunction in these cognitive impairments.

The electrocardiographic, hemodynamic, echocardiographic, and biochemical evaluation of treatment with edaravone on acute cardiac toxicity of aluminum phosphide.

Aluminum phosphide (AlP) poisoning can be highly fatal due to its severe toxicity to the heart. Based on the evidence, edaravone (EDA) has protective effects on various pathological conditions of the heart. This research aimed to examine the potential protective effects of EDA on AlP-induced cardiotoxicity in rats. The rats were divided into six groups, including almond oil (control), normal saline, AlP (LD50), and AlP + EDA (20, 30, and 45 mg/kg). Thirty minutes following AlP poisoning, the electrocardiographic (ECG), blood pressure (BP), and heart rate (HR) parameters were examined for 180 min. The EDA was injected 60 min following the AlP poisoning intraperitoneally. Also, 24 h after poisoning, echocardiography was carried out to evaluate the ejection fraction (EF), stroke volume (SV), and cardiac output (CO). The biochemical and molecular parameters, such as the activities of the mitochondrial complexes, reactive oxygen species (ROS), apoptosis and necrosis, and troponin I and lactate levels, were also examined after 12 and 24 h in the heart tissue. According to the results, AlP-induced ECG abnormalities, decrease in blood pressure, heart rate, SV, EF%, and CO were significantly improved with EDA at doses of 30 and 45 mg/kg. Likewise, EDA significantly improved complex I and IV activity, apoptosis and necrosis, ROS, troponin I, and lactate levels following AlP-poisoning (p < 0.05). Also, the mean survival time was increased following EDA treatment, which can be attributed to the EDA's protective effects against diverse underlying mechanisms of phosphine-induced cardiac toxicity. These findings suggest that EDA, by ameliorating heart function and modulating mitochondrial activity, might relieve AlP-induced cardiotoxicity. Nonetheless, additional investigations are required to examine any potential clinical advantages of EDA in this toxicity.

PEGylated superparamagnetic iron oxide nanoparticles (SPIONs) ameliorate learning and memory deficit in a rat model of Alzheimer's disease: Potential participation of STIMs.

The amyloid-beta (Aß) fibrillation process seems to execute a principal role in the neuropathology of Alzheimer's disease (AD). Accordingly, novel therapeutic plans have concentrated on the inhibition or degradation of Aß oligomers and fibrils. Biocompatible nanoparticles (NPs), e.g., gold and iron oxide NPs, take a unique capacity in redirecting Aß fibrillation kinetics; nevertheless, their impacts on AD-related memory impairment have not been adequately evaluated in vivo. Here, we examined the effect of commercial PEGylated superparamagnetic iron oxide nanoparticles (SPIONs) on the learning and memory of an AD-animal model. The outcomes demonstrated the dose-dependent effect of SPIONs on Aß fibrillation and learning and memory processes. In vitro and in vivo findings revealed that Low doses of SPIONs inhibited Aß aggregation and ameliorated learning and memory deficit in the AD model, respectively. Enhanced level of hippocampal proteins, including brain-derived neurotrophic factor, BDNF, phosphorylated-cAMP response element-binding protein, p-CREB, and stromal interaction molecules, e.g., STIM1 and STIM2, were also observed. However, at high doses, SPIONs did not improve the detrimental impacts of Aß fibrillation on spatial memory and hippocampal proteins expression. Overall, we revealed the potential capacity of SPIONs on retrieval of behavioral and molecular manifestations of AD in vivo, which needs further investigations to determine the mechanistic effect of SPIONs in the AD conundrum.

Bucladesine Attenuates Spatial Learning and Hippocampal Mitochondrial Impairments Induced by 3, 4-Methylenedioxymethamphetamine (MDMA).

Neurotoxic effects of systemic administration of 3, 4- methylenedioxymethamphetamine (MDMA) has been attributed to MDMA and its metabolites. However, the role of the parent compound in MDMA-induced mitochondrial and memory impairment has not yet been investigated. Moreover, it is not yet studied that analogs of 3', 5'-cyclic adenosine monophosphate (cAMP) could decrease these neurotoxic effects of MDMA. We wished to investigate the effects of the central administration of MDMA on spatial memory and mitochondrial function as well as the effects of bucladesine, a membrane-permeable analog of cAMP, on these effects of MDMA. We assessed the effects of pre-training bilateral intrahippocampal infusion of MDMA (0.01, 0.1, 0.5, and 1 µg/side), bucladesine (10 and 100 µM) or combination of them on spatial memory, and different parameters of hippocampal mitochondrial function including the level of reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), mitochondrial swelling, mitochondrial outer membrane damage, the amount of cytochrome c release as well as hippocampal ADP/ATP ratio. The results showed that MDMA caused spatial memory impairments as well as mitochondrial dysfunction as evidenced by the marked increase in hippocampal ADP/ATP ratio, ROS level, the collapse of MMP, mitochondrial swelling, and mitochondrial outer membrane damage leading to cytochrome c release from the mitochondria. The current study also found that bucladesine markedly reduced the destructive effects of MDMA. These results provide evidence of the role of the parent compound (MDMA) in MDMA-induced memory impairments through mitochondrial dysfunction. This study highlights the role of cAMP/PKA signaling in MDMA-induced memory and mitochondrial defects.