The Psychoactive Agent Crocin Can Regulate Hypothalamic-Pituitary-Adrenal Axis Activity

Safranal acts as a neurorestorative agent in rats with cerebral ischemic stroke via upregulating SIRT1

Safranal is an active ingredient of saffron (Crocus sativus L.). Its neuroprotective role in ischemic stroke (IS) through reducing oxidative stress damage has been widely reported. However, the neurorestorative mechanisms of safranal are still in the preliminary stage of exploration. the present study is aimed to discuss the effects of safranal on the recovery of neural function after IS. A middle cerebral artery occlusion/reperfusion (MCAO/R) rat model and an oxygen-glucose deprivation/reoxygenation (OGD/R) model in rat brain microvascular endothelial cells (RBMEC) were established to explore the effects of safranal on IS in vivo and in vitro. It was found that safranal dramatically reduced infarct size and Nissl's body loss in rats subjected to MCAO/R. Safranal also promoted neuron survival, stimulated neurogenesis, induced angiogenesis and increased SIRT1 expression in vivo and in vitro. Silencing of SIRT1 reversed the above effects of safranal on OGD/R-induced RBMEC. The present study indicated that safranal was a promising compound to exert neurorestorative effect in IS via upregulating SIRT1 expression. These results offer insight into developing new mechanisms in the recovery of neural function after safranal treatment of IS.

Crocin nano-chitosan-coated compound improves anxiety disorders, learning, and spatial memory in Alzheimer's model induced by beta-amyloid in rats

Objectives

Alzheimer's disease (AD) is a neurodegenerative disease that results in the gradual breakdown of brain tissue, causing the deterioration of intellectual function and ability. Crocin is a saffron carotenoid compound proven to have excellent neuroprotective and anti-inflammation properties, although it has some limitations such as low stability and bioavailability. Therefore, in the current research, we tried to improve these limitations by using nanotechnology and chitosan as the carrier. Our study examined the therapeutic effects of crocin nano-chitosan-coated compound and compared it with intact crocin in lower dosages than other studies in AD rat models.

Materials and Methods

Encapsulating crocin into chitosan nanoparticles was done through a modified technique to improve its limitations. The AD rat model was induced by bilaterally injecting beta-amyloid (Aβ) peptide into the frontal lobe using a stereotaxic device. To evaluate memory, we conducted the Barnes maze test, and to evaluate anxiety, we used the elevated plus maze test. Also, histological tests were conducted to evaluate neuronal damage in each group.

Results

Crocin nano-chitosan-coated administration significantly improved specific memory indicators compared to the Aβ and other treated groups. A significant decrease in anxiety indicators was detected compared to the Aβ and other treated groups. Finally, the results of hippocampus staining indicated a meaningful difference between the Aβ group and other treated groups, compared to the crocin nano-chitosan-coated group.

Conclusion

Treatment with low dosages of crocin in the nano-coated form exhibited great efficacy in reducing AD's adverse effects compared to the same dosage of intact crocin.

Emphasizing the Crosstalk Between Inflammatory and Neural Signaling in Post-traumatic Stress Disorder (PTSD)

Post-traumatic stress disorder (PTSD) is a chronic incapacitating condition with recurrent experience of trauma-related memories, negative mood, altered cognition, and hypervigilance. Agglomeration of preclinical and clinical evidence in recent years specified that alterations in neural networks favor certain characteristics of PTSD. Besides the disruption of hypothalamus-pituitary-axis (HPA) axis, intensified immune status with elevated pro-inflammatory cytokines and arachidonic metabolites of COX-2 such as PGE2 creates a putative scenario in worsening the neurobehavioral facet of PTSD. This review aims to link the Diagnostic and Statistical Manual of mental disorders (DSM-V) symptomology to major neural mechanisms that are supposed to underpin the transition from acute stress reactions to the development of PTSD. Also, to demonstrate how these intertwined processes can be applied to probable early intervention strategies followed by a description of the evidence supporting the proposed mechanisms. Hence in this review, several neural network mechanisms were postulated concerning the HPA axis, COX-2, PGE2, NLRP3, and sirtuins to unravel possible complex neuroinflammatory mechanisms that are obscured in PTSD condition.

Effects of Aqueous Saffron Extract on Glucoregulation as Well as Hepatic Agt and TNF-α Gene Expression in Rats Subjected to Sub-Chronic Stress

Background

Stress and saffron seem to affect glucoregulation mechanisms and insulin resistance in different ways. Impacts of the aqueous saffron extract were investigated on serum glucose levels, serum insulin levels, the homeostatic model assessment of β-cell function (HOMA-B), the homeostatic model assessment of insulin resistance (HOMA-IR), adrenal weight, and hepatic gene expression of angiotensinogen (Agt) and tumor necrosis factor-α (TNF-α) in rats under sub-chronic stress.

Materials and Methods

Forty-two male rats were divided into six groups: control, restraint stress (6h/day for seven days), saffron (30 and 60 mg/kg) treatments for seven days, and post-stress saffron (30 and 60 mg/kg) treatments for seven days. The serum glucose and insulin levels, hepatic gene expressions of Agt and TNF-α, HOMA-IR, HOMA-B, and adrenal gland weight were measured.

Results

One-week recovery following sub-chronic stress led to non-significant hyperglycemia, hyperinsulinemia, and insulin resistance. The hepatic Agt and TNF-α mRNA levels increased significantly in this group. Saffron administration led to enhanced hepatic Agt mRNA in the non-stressed subjects. In addition, serum glucose levels, insulin resistance, and hepatic Agt gene expression significantly increased in stress-saffron groups. The hepatic TNF-α gene expression was reduced only in the stress-saffron 60 group.

Conclusion

Saffron treatment after sub-chronic stress not only did not improve glucose tolerance but also enhanced insulin resistance. It indicated the interaction of saffron and sub-chronic stress to promote renin-angiotensin system activity. In addition, the saffron treatment decreased TNF-α gene expression after sub-chronic stress. The synergistic stimulating effect of saffron and sub-chronic stress on gene expression of hepatic Agt led to insulin resistance and hyperglycemia.

Therapeutic effects of saffron extract on different memory types, anxiety, and hippocampal BDNF and TNF-α gene expressions in sub-chronically stressed rats

Objective: While stress reportedly impairs memory, saffron enhances it. This study investigated the therapeutic effects of saffron extract on different memory types, anxiety-like behavior, and expressions of BDNF and TNF-α genes in sub-chronically stressed rats.Methods: Rats were randomly assigned to control, restraint stress (6 h/day/7 days), two 7-days saffron treatments with 30 and 60 mg/kg, and two stress-saffron groups (30 and 60 mg/kg/7 post-stress days). Serum cortisol level and hippocampal BDNF and TNF-α gene expressions were measured. Open field, passive avoidance, novel object recognition, and object location tests were performed to assess anxiety-like behavior and avoidance as well as cognitive and spatial memories, respectively.Results: The low saffron dose in the sub-chronic stressed group led to a significant increase in passive avoidance latency from day 3 onward whereas this effect was observed after 7 days under the high-dose treatment that simultaneously led to a significant decline in serum cortisol level. While the low saffron dose led to a sharp drop in hippocampal TNF-α gene expression, the high dose significantly increased the hippocampal BDNF gene expression in the sub-chronic stress group. Finally, both saffron doses reduced anxiety in the stressed groups.Conclusion: Compared to the low saffron dose, the high dose had a latent but long-lasting impact. Cognitive and spatial memories remained unaffected by either stress or saffron treatment. In addition, only the high saffron dose reversed anxiety in the sub-chronically stressed group. These findings suggest that various doses of saffron act differently on different brain functions under sub-chronic stress conditions.Abbreviations: Brain derived neurotrophic factor (BDNF), tumor necrosis factor-α (TNF-α), hypothalamic-pituitary-adrenal axis (HPA), novel object recognition task (NORT), novel object location task (NOLT), open field test (OFT), passive avoidance (PA).

Association between chronic stress and Alzheimer's disease: Therapeutic effects of Saffron

Chronic stress and high levels of glucocorticoids produce functional and structural changes in brain and especially in the hippocampus, an important limbic system structure that plays a key role in cognitive functions including learning and memory. Alzheimer's disease (AD) is a chronic neurodegenerative disease that usually starts slowly and worsens over time. Indeed, cognitive dysfunction, neuronal atrophy, and synaptic loss are associated with both AD and chronic stress. Recent preclinical and clinical studies have highlighted a possible link between chronic stress, cognitive decline and the development of AD. It is suggested that Tau protein is an essential mediator of the neurodegenerative effects of stress and glucocorticoids towards the development of AD pathology. Recent findings from animal and humans studies demonstrated that saffron and its main constitutive crocin are effective against chronic stress-induced cognitive dysfunction and oxidative stress and slowed cognitive decline in AD. The inhibitory actions on acetylcholinesterase activity, aggregation of beta-amyloid protein into amyloid plaques and tau protein into neurofibrillary tangles, and also the antioxidant, anti-inflammatory, and the promotion of synaptic plasticity effects are among the possible mechanisms to explain the neuroprotective effects of saffron. New evidences demonstrate that saffron and its main component crocin might be a promising target for cognition improvement in AD and stress-related disorders.

Comparison of the Effects of Deep Brain Stimulation of the Prelimbic Cortex and Basolateral Amygdala for Facilitation of Extinction Process of Conditioned Fear

Background: The study of the biological basis of fear in animal models has progressed considerably because of the energy and space that the brain devotes to this basic emotion. Electrical stimulation targets several structures of the brain to examine its behavioral effects and to understand the role of different regions in underlying mechanisms of fear processing and anxiety in preclinical models. Objectives: In this study, the effects of high-frequency deep brain stimulation (DBS) of the basolateral amygdala (BLA) and prelimbic (PL) sub-region of the prefrontal cortex were evaluated on the extinction process of conditioned fear. Methods: This study was performed on 35 male Wistar rats in the weight range of 220 – 250 g. After selecting the animals, they were separated into five groups. Then, we did stereotactic surgery on rats for electrode implantation. After recovery, some rats were conditioned, followed by a 10-day treatment schedule via high-frequency DBS in the BLA or PL. Next, freezing behavior was measured as a predicted response dedicated to extinction, without shock (re-exposure). In addition, we used ELISA and Western blot to estimate blood serum corticosterone levels and c-Fos protein expression. Results: The mean freezing time recorded for the PL group was significantly lower than that of both the BLA group and the PC group (P < 0.01). The BLA group and PC group were also significantly different (P < 0.001). Corticosterone results indicated that the PL group had significantly higher serum corticosterone levels compared with both the BLA group and the PC group (P < 0.01). In addition, the BLA group revealed a significant reduction in c-Fos expression compared with the PC (P < 0.001). Conclusions: This study provides further evidence for the contribution of the prelimbic cortex and amygdala both in acquisition and extinction processes during contextual fear conditioning. However, the PL stimulation by high-frequency DBS might be more involved in the extinction process and play a more important role as an enhancer.

Protective properties of the aqueous extract of saffron (Crocus sativus L.) in ischemic stroke, randomized clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Crocus sativus L. has been used throughout the world in traditional medicine as a treatment for neurological disorders such as depression. Growing attention is currently being paid to the use of neuroprotective agents in ischemic strokes.

AIM OF THE STUDY

This study assed the effect of saffron as a neuroprotective natural product in cerebral ischemia in human.

STUDY DESIGN

Patients with acute ischemic stroke were randomly allocated to receive either routine stroke care (control group, n = 20) or routine care plus aqueous extract of saffron capsule (200 mg/day) (saffron-treated group, n = 19). Both groups were monitored during their four-day hospital stay and the three-month follow-up period. The groups were compared in terms of short- and long-term effects of saffron capsules using the National Institute of Health Stoke Scale (NIHSS), Barthel Scale, and serum neuron specific enolase (NSE), Brain-derived neurotrophic factor (BDNF), S100 levels.

RESULTS

Based on the NIHSS, the severity of stroke during the first four days was significantly lower in the saffron-treated group than in the control group (P < 0.05). Compared to the levels on the first day, serum NSE and s100 levels were significantly decreased and BDNF concentration was increased in the saffron-treated group on the fourth day. Also, our results showed there was a negative significant non-linear cubic regression between BDNF concentration and score of NIHSS. At the end of the three-month follow-up period, the mean Barthel index was significantly higher in the saffron-treated group than in the control group (P < 0.001).

CONCLUSION

The results of this study confirmed the short and long-term neuroprotective effects of aqueous extract of saffron on ischemic stroke in humans.

Deep brain stimulation in a rat model of post-traumatic stress disorder modifies forebrain neuronal activity and serum corticosterone

Objective(s):

Post-traumatic stress disorder (PTSD), one of the most devastating kinds of anxiety disorders, is the consequence of a traumatic event followed by intense fear. In rats with contextual fear conditioning (CFC), a model of PTSD caused by CFC (electrical foot shock chamber), deep brain stimulation (DBS) alleviates CFC abnormalities.

Materials and Methods:

Forty Male Wistar rats (220–250 g) were divided into 5 groups (n=8) and underwent stereotactic surgery to implant electrodes in the right basolateral nucleus of the amygdala (BLn). After 7 days, some animals received a foot shock, followed by another 7-day treatment schedule (DBS treatment). Next, freezing behavior was measured as a predicted response in the absence of the foot shock (re-exposure time). Blood serum corticosterone levels and amygdala c-Fos protein expression were assessed using Enzyme-linked immunosorbent assay (ELISA) and Western blot, respectively. Furthermore, freezing behaviors by re-exposure time test and general anxiety by elevated plus-maze (EPM) were evaluated.

Results:

PTSD decreased serum corticosterone levels and increased both amygdala c-Fos expression and freezing behaviors. Therefore, DBS treatment significantly (P<0.001) enhanced serum corticosterone levels and could significantly (P<0.001) reduce both c-Fos protein expression and freezing behaviors’ duration. However, DBS treatment has no effect on the general anxiety in PTSD rats.

Conclusion:

We argue that these outcomes might demonstrate the mechanism of DBS treatment, a complete therapeutic strategy, in PTSD patients.

Prediction of Molecular Mechanisms for LianXia NingXin Formula: A Network Pharmacology Study

Objectives: Network pharmacological methods were used to investigate the underlying molecular mechanisms of LianXia NingXin (LXNX) formula, a Chinese prescription, to treat coronary heart disease (CHD) and disease phenotypes (CHD related diseases and symptoms).

Methods: The different seed gene lists associated with the herbs of LXNX formula, the CHD co-morbid diseases and symptoms which were relieved by the LXNX formula (co-morbid diseases and symptoms) were curated manually from biomedical databases and published biomedical literatures. Module enrichment analysis was used to identify CHD-related disease modules in the protein–protein interaction (PPI) network which were also associated to the targets of LXNX formula (LXNX formula’s CHD modules). The molecular characteristics of LXNX formula’s CHD modules were investigated via functional enrichment analysis in terms of gene ontology and pathways. We performed shortest path analysis to explore the interactions between the drug targets of LXNX formula and CHD related disease phenotypes (e.g., co-morbid diseases and symptoms).

Results: We identified two significant CHD related disease modules (i.e., M146 and M203), which were targeted by the herbs of LXNX formula. Pathway and GO term functional analysis results indicated that G-protein coupled receptor signaling pathways (GPCR) of M146 and cellular protein metabolic process of M203 are important functional pathways for the respective module. This is further confirmed by the shortest path analysis between the drug targets of LXNX formula and the aforementioned disease modules. In addition, corticotropin releasing hormone (CRH) and natriuretic peptide precursor A (NPPA) are the only two LXNX formula target proteins with the low shortest path length (on average shorter than 3) to their respective CHD module and co-morbid disease and symptom gene groups.

Conclusion: G-protein coupled receptor signaling pathway and cellular protein metabolic process are the key LXNX formula’s pathways to treat CHD disease phenotypes, in which CRH and NPPA are the two key drug targets of LXNX formula. Further evidences from Chinese herb pharmacological databases indicate that Pinellia ternata (Banxia) has relatively strong adjustive functions on the two key targets.