Apamin induces plastic changes in hippocampal neurons in senile Sprague-Dawley rats

Bee venom ameliorates oxidative stress and histopathological changes of hippocampus, liver and testis during status epileptics

The unrelenting progression of neurodegenerative diseases has a negative impact on affected individuals, their families, and society. Recurrent epileptic seizures are the hallmark of epilepsy, and treating it effectively remains difficult. Clarify and understanding effects of the antiepileptic drugs (AEDs) in epilepsy by comparing the therapeutic effects between rats receiving valproic acid (VPA) and Bee venom (BV) was aimed throughout the present study. Four male Wistar rat groups were included: control, epileptic group receiving pilocarpine (PILO), epileptic group treated with VPA and BV respectively. Cognitive functions were assessed by evaluating latency time in hot plate, despair swim test, grooming, rearing and ambulation frequency in the open field. BV has ameliorative effect on electrolytes balancing, assured by decreasing lipid peroxidation, nitric oxide and increasing catalase, superoxide dismutase and glutathione peroxidase activities. BV enhanced restoration of liver functions indicated by alanine transaminase (ALT) and aspartate transaminase (AST), total proteins, and albumin; hormonal parameters total and free testosterone, follicle stimulating hormone (FSH) and Luteinizing hormone (LH) were preserved by BV with great recovery of hippocampus, liver and testicular histopathology and ultrastructure comparing with the epileptic rats. The present findings suggested that BV and its active components offer fresh options for controlling epilepsy and prospective methods via minimize or manage the severe consequences.

Cellular mechanisms in brain aging: Focus on physiological and pathological aging

Aging is a natural phenomenon characterized by accumulation of cellular damage and debris. Oxidative stress, cellular senescence, sustained inflammation, and DNA damage are the main cellular processes characteristic of aging associated with morphological and functional decline. These effects tend to be more pronounced in tissues with high metabolic rates such as the brain, mainly in regions such as the prefrontal cortex, hippocampus, and amygdala. These regions are highly related to cognitive behavior, and therefore their atrophy usually leads to decline in processes such as memory and learning. These cognitive declines can occur in physiological aging and are exacerbated in pathological aging. In this article, we review the cellular processes that underlie the triggers of aging and how they relate to one another, causing the atrophy of nerve tissue that is typical of aging. The main topic of this review to determine the central factor that triggers all the cellular processes that lead to cellular aging and discriminate between normal and pathological aging. Finally, we review how the use of supplements with antioxidant and anti-inflammatory properties reduces the cognitive decline typical of aging, which reinforces the hypothesis of oxidative stress and cellular damage as contributors of physiological atrophy of aging. Moreover, cumulative evidence suggests their possible use as therapies, which improve the aging population's quality of life.

Highly Stretchable Hydrogels as Wearable and Implantable Sensors for Recording Physiological and Brain Neural Signals

Recording electrophysiological information such as brain neural signals is of great importance in health monitoring and disease diagnosis. However, foreign body response and performance loss over time are major challenges stemming from the chemomechanical mismatch between sensors and tissues. Herein, microgels are utilized as large crosslinking centers in hydrogel networks to modulate the tradeoff between modulus and fatigue resistance/stretchability for producing hydrogels that closely match chemomechanical properties of neural tissues. The hydrogels exhibit notably different characteristics compared to nanoparticles reinforced hydrogels. The hydrogels exhibit relatively low modulus, good stretchability, and outstanding fatigue resistance. It is demonstrated that the hydrogels are well suited for fashioning into wearable and implantable sensors that can obtain physiological pressure signals, record the local field potentials in rat brains, and transmit signals through the injured peripheral nerves of rats. The hydrogels exhibit good chemomechanical match to tissues, negligible foreign body response, and minimal signal attenuation over an extended time, and as such is successfully demonstrated for use as long-term implantable sensory devices. This work facilitates a deeper understanding of biohybrid interfaces, while also advancing the technical design concepts for implantable neural probes that efficiently obtain physiological information.

Anti-inflammatory activities of arthropod peptides: a systematic review

Peptides obtained from different animal species have gained importance recently due to research that aims to develop biopharmaceuticals with therapeutic potential. In this sense, arthropod venoms have drawn attention, not only because of their toxicity but mainly for the search for molecules with various bioactivities, including anti-inflammatory activity. The purpose of the present study is to gather data available in the literature on new peptides derived from arthropod species with anti-inflammatory potential. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Studies on peptides from arthropods that display anti-inflammatory activity were retrieved from PubMed, Scopus, Web of Science, and Google Scholar databases. The bibliographic research started in 2020 and searched papers without a limit on the publication date. The articles were analyzed using a search string containing the following terms: "Peptides" and "Anti-inflammatory", in combinations such as "Ant", "Bee", "Wasp", "Crab", "Shrimp", "Scorpion", "Spider", "Tick" and "Centipedes". Besides, a search was carried out in the databases with the terms: "Peptides", "Antitumor", or "Anticancer", and "Arthropods". Articles that met the inclusion and exclusion criteria totalized 171, and these served for data extraction. Additionally, the present review included anti-inflammatory peptides with anticancer properties. Peptides with confirmed anti-inflammatory activity were from insects (ants, bees, and wasps), crustaceans (shrimp and crabs), arachnids (scorpions, spiders, and ticks), and centipedes. These arthropod peptides act mainly by decreasing pro-inflammatory cytokines as analyzed in vitro and in vivo. Some showed significant antineoplastic activity, working in essential cellular pathways against malignant neoplasms.

Natural products present neurotrophic properties in neurons of the limbic system in aging rodents

Aging is a complex process that can lead to neurodegeneration and, consequently, several pathologies, including dementia. Physiological aging leads to changes in several body organs, including those of the central nervous system (CNS). Morphological changes in the CNS and particularly the brain result in motor and cognitive deficits affecting learning and memory and the circadian cycle. Characterizing neural modifications is critical to designing new therapies to target aging and associated pathologies. In this review, we compared aging to the changes occurring within the brain and particularly the limbic system. Then, we focused on key natural compounds, apamin, cerebrolysin, Curcuma longa, resveratrol, and N-PEP-12, which have shown neurotrophic effects particularly in the limbic system. Finally, we drew our conclusions delineating future perspectives for the development of novel natural therapeutics to ameliorate aging-related processes.

Subchronic cerebrolysin treatment alleviates cognitive impairments and dendritic arborization alterations of granular neurons in the hippocampal dentate gyrus of rats with temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is one of the most frequent forms of focal epilepsy; patients with this condition, in addition to exhibiting complex seizures, also exhibit cognitive deficits. In the temporal lobe, the hippocampus, a structure relevant to learning and memory processes, is particularly affected by epilepsy. In animal models of TLE induced by pilocarpine, learning and memory deficiencies associated with changes in synaptic plasticity of the hippocampus have been reported. Cerebrolysin (CBL) is a biologically active mixture of low molecular weight peptides with neuroprotective and neurotrophic effects. The objective of the present study was to determine whether subchronic CBL treatment of rats in the chronic phase of TLE reduces the number and intensity of seizures, and whether CBL treatment can improve cognitive deficits (learning and spatial memory) and dendritic morphology in granular dentate neurons of the hippocampus. Temporal lobe epilepsy (lithium-pilocarpine model) was induced in male Wistar rats (weight, 250-300 g). Two epileptic groups were studied, in which CBL (538 mg/kg) or vehicle was administered intraperitoneally for 5 consecutive days per week for 3 weeks. Respective controls were also included in the study. At the end of treatment, the Barnes maze test (BMT) was used to assess spatial navigational learning and memory. The dendritic morphology of the dentate gyrus was also evaluated using the Golgi-Cox staining method. Results of this study did not support an antiepileptic effect of CBL. Epileptic animals treated with this agent exhibited secondarily generalized seizures similar in frequency and intensity to those of epileptic animals treated only with vehicle. However, when analyzing dendritic morphology of hippocampal granular neurons in these animals, CBL appeared to attenuate dendritic deterioration caused by epilepsy, which was associated with improved cognitive performance of the CBL-treated animals in the BMT compared with vehicle-treated epileptic rats. In conclusion, although CBL did not exert an anticonvulsant effect against secondarily generalized seizures, it can be proposed for use as an add-on therapy in epilepsy management to prevent neuronal alterations, and to improve memory and learning processes.

Consequences of diabetes mellitus on neuronal connectivity in limbic regions

Diabetes mellitus (DM) is characterized by high levels of blood glucose. In recent years, its prevalence has increased, which was 422 million in the world in 2014. In elderly patients, DM is associated with deficits in memory and learning processes. The cognitive deficits lead to dementia. With the development of animal models in DM, it has been possible to better understand quantitative morphological changes in numerous neuronal structures belonging to the limbic system, such as the prefrontal cortex (PFC), the hippocampus and basolateral amygdala (BLA). These structures are in close relationship with processes of memory and learning. Several reports have demonstrated that chronic hyperglycemia reduces spinogenesis and dendritic arborization in the aforementioned regions along with a decline in memory and learning processes, especially in streptozotocin (STZ)-induced diabetic rats. In the present review, we discuss animal models, the effects of chronic hyperglycemia on dendritic morphology of limbic regions and memory and learning processes, the effect on neural transmission in these regions, the pathologic mechanisms involved, and the relevance of dendritic morphology in diabetes. All of this information can help us to have a better understanding of dementia in diabetes mellitus and propose strategies for its prevention and treatment.

Bee venom therapy: Potential mechanisms and therapeutic applications

Bee venom is a very complex mixture of natural products extracted from honey bee which contains various pharmaceutical properties such as peptides, enzymes, biologically active amines and nonpeptide components. The use of bee venom into the specific points is so called bee venom therapy, which is widely used as a complementary and alternative therapy for 3000 years. A growing number of evidence has demonstrated the anti-inflammation, the anti-apoptosis, the anti-fibrosis and the anti-arthrosclerosis effects of bee venom therapy. With these pharmaceutical characteristics, bee venom therapy has also been used as the therapeutic method in treating rheumatoid arthritis, amyotrophic lateral sclerosis, Parkinson's disease, Alzheimer's disease, liver fibrosis, atherosclerosis, pain and others. Although widely used, several cases still reported that bee venom therapy might cause some adverse effects, such as local itching or swelling. In this review, we summarize its potential mechanisms, therapeutic applications, and discuss its existing problems.

Antidepressant effects of acupoint stimulation and fluoxetine by increasing dendritic arborization and spine density in CA1 hippocampal neurons of socially isolated rats

Given the importance of depression and the adverse effects of conventional treatment, it is necessary to seek complementary therapies. In a rat model of depression, this study aimed to assess the behavioral and morphological effects of embedding absorbable thread in acupoints (acu-catgut), and compare the results to those of fluoxetine treatment and the corresponding control groups. Therefore, depressive-like behavior was evaluated with the forced swimming test, and dendritic morphology (in the CA1 hippocampal region) with the Golgi-Cox technique and Sholl analysis. After weaning, male Sprague-Dawley rats were housed in social isolation for 8 weeks to induce depressive-like behavior. They were then given a 21-day treatment by stimulating acupoints with acu-catgut (AC) or fluoxetine (FX) (2 mg/kg). Rats were divided into six groups: Control (socially housed), social isolation (SI), SI + AC, SI + Sham (sham embedding of thread), SI + FX and SI + VH (vehicle). Compared to fluoxetine, acu-catgut treatment was more effective in reversing depressive-like behavior elicited by SI. The SI-induced reduction in dendritic length and spine density in hippocampal CA1 pyramidal neurons was attenuated after prolonged treatment with acu-catgut or fluoxetine. Hence, both treatments proved capable of reversing depressive-like alterations caused by SI, likely due to dendritic remodeling in the hippocampus.

Peptides isolated from animal venom as a platform for new therapeutics for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease that deeply affects patients, their family and society. Although scientists have made intense efforts in seeking the cure for AD, no drug available today is able to stop AD progression. In this context, compounds isolated from animal venom are potentially successful drugs for neuroprotection, since they selectively bind to nervous system targets. In this review, we presented different studies using peptides isolated from animal venom for the treatment of AD. This is a growing field that will be very helpful in understanding and even curing neurodegenerative diseases, especially AD.

Neuroactive compounds obtained from arthropod venoms as new therapeutic platforms for the treatment of neurological disorders

The impact of neurological disorders in society is growing with alarming estimations for an incidence increase in the next decades. These disorders are generally chronic and can affect individuals early during productive life, imposing real limitations on the performance of their social roles. Patients can have their independence, autonomy, freedom, self-image, and self-confidence affected. In spite of their availability, drugs for the treatment of these disorders are commonly associated with side effects, which can vary in frequency and severity. Currently, no effective cure is known. Nowadays, the biopharmaceutical research community widely recognizes arthropod venoms as a rich source of bioactive compounds, providing a plethora of possibilities for the discovery of new neuroactive compounds, opening up novel and attractive opportunities in this field. Several identified molecules with a neuropharmacological profile can act in the central nervous system on different neuronal targets, rendering them useful tools for the study of neurological disorders. In this context, this review aims to describe the current main compounds extracted from arthropod venoms for the treatment of five major existing neurological disorders: stroke, Alzheimer’s disease, epilepsy, Parkinson’s disease, and pathological anxiety.

Apitoxin protects rat pups brain from propionic acid-induced oxidative stress: The expression pattern of Bcl-2 and Caspase-3 apoptotic genes

The primary aim of this study was to determine the potential modulatory role of the apitoxin (bee venom; BV) against propionic acid (PPA)-induced neurotoxicity. The biochemical responses to PPA exposure in rat pups were assayed, including changes in the antioxidant barrier systems and lipid peroxidation and protein oxidation biomarkers in the brain tissue. DNA damage was measured by single-cell gel electrophoresis and differences in Bcl-2 and Caspase-3 mRNA expression were assessed using real-time PCR. Changes in amygdala complex ultrastructure were visually assessed using electron microscopy. Sixty rat pups were assigned into six groups: a control group, a PPA-treated group, a BV-treated group, a protective co-treated group, a therapeutic co-treated group, and a protective/therapeutic co-treated group. The results indicate that PPA induced a pronounced increase (64.6%) in malondialdehyde (MDA), and in DNA damage (73.3%) with three-fold increase in protein carbonyl concentration. A significant reduction was observed in the enzyme activities of superoxide dismutase (SOD) (48.7%) and catalase (CAT) (74.8%) and reduced glutathione (GSH) level (52.6%). BV significantly neutralized the PPA-induced oxidative stress effects, especially in the BV protective/therapeutic co-treated group. In this group, GSH levels were restored to 64.5%, and MDA, protein carbonyl levels and tail moment % were diminished by 69.5, 21.1 and 18.8% relative to the control, respectively. Furthermore, while PPA induced significant apoptotic neural cell death, BV markedly inhibited apoptosis by promoting Bcl-2 expression and blocking Caspase-3 expression. BV markedly restored the normal ultrastructural morphology of the amygdala complex neurons. These results conclusively demonstrate that BV administration provides both protective and therapeutic effects in response to the PPA-induced deleterious effects, including oxidative stress, DNA damage, and neuronal death in the brains of rat pups.

Bee venom effects on ubiquitin proteasome system in hSOD1(G85R)-expressing NSC34 motor neuron cells

Background

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that results from a progressive loss of motor neurons. Familial ALS (fALS) is caused by missense mutations in Cu, Zn-superoxide dismutase 1 (SOD1) that frequently result in the accumulation of mutant protein aggregates that are associated with impairments in the ubiquitin-proteasome system (UPS). UPS impairment has been implicated in many neurological disorders. Bee venom (BV) extracted from honey bees has been used as a traditional medicine for treating inflammatory diseases and has been shown to attenuate the neuroinflammatory events that occur in a symptomatic ALS animal model.

Methods

NSC34 cells were transiently transfected with a WT or G85R hSOD1-GFP construct for 24 hrs and then stimulated with 2.5 μg/ml BV for 24 hrs. To determine whether a SOD1 mutation affects UPS function in NSC34 cells, we examined proteasome activity and performed western blotting and immunofluorescence using specific antibodies, such as anti-misfolded SOD1, anti-ubiquitin, anti-GRP78, anti-LC3, and anti-ISG15 antibodies.

Results

We found that GFP-hSOD1^G85R overexpression induced SOD1 inclusions and reduced proteasome activity compared with the overexpression of GFP alone in NSC34 motor neuronal cells. In addition, we also observed that BV treatment restored proteasome activity and reduced the accumulation of ubiquitinated and misfolded SOD1 in GFP-hSOD1^G85R-overexpressing NSC34 motor neuronal cells. However, BV treatment did not activate the autophagic pathway in these cells.

Conclusion

Our findings suggest that BV may rescue the impairment of the UPS in ALS models.

K(Ca)2 and k(ca)3 channels in learning and memory processes, and neurodegeneration

Calcium-activated potassium (K_Ca) channels are present throughout the central nervous system as well as many peripheral tissues. Activation of K_Ca channels contribute to maintenance of the neuronal membrane potential and was shown to underlie the afterhyperpolarization (AHP) that regulates action potential firing and limits the firing frequency of repetitive action potentials. Different subtypes of K_Ca channels were anticipated on the basis of their physiological and pharmacological profiles, and cloning revealed two well defined but phylogenetic distantly related groups of channels. The group subject of this review includes both the small conductance K_Ca2 channels (K_Ca2.1, K_Ca2.2, and K_Ca2.3) and the intermediate-conductance (K_Ca3.1) channel. These channels are activated by submicromolar intracellular Ca²⁺ concentrations and are voltage independent. Of all K_Ca channels only the K_Ca2 channels can be potently but differentially blocked by the bee-venom apamin. In the past few years modulation of K_Ca channel activation revealed new roles for K_Ca2 channels in controlling dendritic excitability, synaptic functioning, and synaptic plasticity. Furthermore, K_Ca2 channels appeared to be involved in neurodegeneration, and learning and memory processes. In this review, we focus on the role of K_Ca2 and K_Ca3 channels in these latter mechanisms with emphasis on learning and memory, Alzheimer’s disease and on the interplay between neuroinflammation and different neurotransmitters/neuromodulators, their signaling components and K_Ca channel activation.