Despite the growing interest in cell- and exosome-based therapies for neurological diseases including Alzheimer's disease (AD), there is still a gap in the investigation of more effective treatments i Show more
Despite the growing interest in cell- and exosome-based therapies for neurological diseases including Alzheimer's disease (AD), there is still a gap in the investigation of more effective treatments in terms of efficacy, safety, and durability of effect. This study aimed to compare the therapeutic potential of astrocyte cells and their derived exosomes (AS-Exos) in restoring cognitive function in a mouse model of AD. AD model was induced by bilateral electrical lesioning of the nucleus basalis of Meynert (NBM). Astrocytes were isolated from neonatal rat brains, and AS-Exos were harvested from astrocyte-conditioned media using an AnaCell extraction kit. Seven days after lesion induction, astrocytes and AS-Exos were stereotaxically injected into the NBM. Four weeks later, behavioral assessments (passive avoidance and locomotor activity), electrophysiological recordings (EEG), and biochemical measurements of hippocampal brain-derived neurotrophic factor (BDNF) and acetylcholine (ACh) levels were performed. AS-Exos were confirmed as cup-shaped vesicles (30-150 nm) expressing the exosomal surface markers CD9, CD63, and CD81. NBM lesions significantly reduced step-through latency (STL), hippocampal BDNF and ACh levels, and disrupted EEG oscillatory patterns. Treatment with AS-Exos markedly improved STL and produced greater increases in hippocampal BDNF and ACh levels compared with AD and AD+saline groups. EEG analysis also revealed enhanced beta, alpha, and gamma power, with the most robust normalization observed in the AS-Exos group. AS-Exos demonstrated superior biochemical and electrophysiological benefits compared with astrocyte transplantation and provided equal or greater improvement in behavioral outcomes. These findings highlight AS-Exos as a promising cell-free therapeutic strategy for alleviating cognitive deficits associated with AD. Show less
The transport of pharmaceutical compounds into aquatic ecosystems poses a significant environmental threat, particularly due to the presence of drugs that cannot be completely removed during wastewate Show more
The transport of pharmaceutical compounds into aquatic ecosystems poses a significant environmental threat, particularly due to the presence of drugs that cannot be completely removed during wastewater treatment processes. Diclofenac (DCF), one of the most widely used nonsteroidal anti-inflammatory drugs worldwide, is among the pharmaceuticals frequently detected in aquatic environments due to its high consumption levels and persistence in the environment. It is known that this compound causes neurotoxicity, behavioral disorders, and physiological stress responses in aquatic organisms even at low concentrations. This study aimed to determine the effects of diclofenac exposure on oxidative stress, circadian rhythm, and behavioral parameters in zebrafish larvae. For this purpose, zebrafish embryos and early-stage larvae were exposed to DCF at concentrations of 0.5, 2.5, and 12.5 μg/L for 120 h. Subsequently, to investigate the effect of DCF on oxidative stress, SOD, CAT, GPX, and AChE enzyme activities and gene expression levels were analyzed. To examine its effects on behavior and circadian rhythm, thigmotaxis and locomotor activity analyses were performed. Additionally, to determine the molecular-level effects of behavioral changes, the expression levels of the bdnf, 5ht4, crhr, bmal1, per, and gnat2 genes were analyzed. Overall, our findings indicate that DCF affects behavioral activity, neurotransmitter metabolism, oxidative stress response, circadian rhythm, and retina-related molecular regulators in zebrafish larvae in a multilevel manner. These results highlight the potential risks of pharmaceutical contaminants on neurodevelopmental processes in aquatic ecosystems and demonstrate that even environmental doses can produce complex responses in biological systems. Show less
Extended periods of microgravity during orbital flights can impair astronauts' cognitive abilities, including learning and memory, posing a persistent health concern in the field of aerospace medicine Show more
Extended periods of microgravity during orbital flights can impair astronauts' cognitive abilities, including learning and memory, posing a persistent health concern in the field of aerospace medicine. The study examined the pharmacological effects of agmatine and its influence on simulated neurobehavioral changes in rats under microgravity conditions. Rats were exposed to simulated microgravity (SMG) conditions using the hindlimb unloading (HU) model for 28 days and evaluated for behavioural alterations using the open field test, elevated plus maze, and forced swim test, and cognitive deficits using the novel object recognition test and Morris water maze. Further, brain agmatine levels, neurochemical and structural alterations in the hippocampus, and prefrontal cortex were examined. Chronic agmatine treatment dose-dependently (40 and 80mg/kg) and its endogenous modulation by l-arginine, and aminoguanidine prevented behavioral and cognitive deficits by improving exploratory behaviour, reducing anxiety-depressive-like symptoms, and enhancing cognitive performance. Our findings reported a significant reduction in agmatine levels in the hippocampus and prefrontal cortex in SMG conditions. Agmatine administration and its modulation normalized neurotransmitter imbalances, especially by restoring the reduced levels of gamma-aminobutyric acid, dopamine, and serotonin, along with a reduction of elevated levels of glutamate in SMG conditions. Moreover, agmatine decreased reactive oxygen species production, enhanced hippocampal antioxidant enzyme activities, suppressed pro-inflammatory cytokines (TNF-α, IL-6), and improved IL-10 and brain-derived neurotrophic factor levels in HU rats. Moreover, agmatine and its endogenous modulation preserved neuronal cells of the hippocampus and prefrontal cortex. In conclusion, the present study suggests that agmatine administration and modulation of endogenous agmatine levels effectively mitigate SMG-induced neurological dysregulation through neuroprotection and neuromodulation. Understanding the neurobiological mechanisms underlying these effects opens up new possibilities for creating novel interventions targeting agmatinergic signaling in spaceflight conditions and associated complications. Show less