Ameliorative effect of imperatorin in chemically induced fibromyalgia: Role of NMDA/NFkB mediated downstream signaling

Astaxanthin alleviates fibromyalgia pain and depression via NLRP3 inflammasome inhibition

Fibromyalgia is characterised by widespread chronic pain and is often accompanied by comorbidities such as sleep disorders, anxiety, and depression. Because it is often accompanied by many adverse symptoms and lack of effective treatment, it is important to search for the pathogenesis and treatment of fibromyalgia. Astaxanthin, a carotenoid pigment known for its anti-inflammatory and antioxidant properties, has demonstrated effective analgesic effects in neuropathic pain. However, its impact on fibromyalgia remains unclear. Therefore, in this study, we constructed a mouse model of fibromyalgia and investigated the effect of astaxanthin on chronic pain and associated symptoms through multiple intragastrical injections. We conducted behavioural assessments to detect pain and depression-like states in mice, recorded electroencephalograms to monitor sleep stages, examined c-Fos activation in the anterior cingulate cortex, measured activation of spinal glial cells, and assessed levels of inflammatory factors in the brain and spinal cord, including interleukin (IL)-1β, IL-6, and tumour necrosis factor- α(TNF-α).Additionally, we analysed the expression levels of IL-6, IL-10, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), Apoptosis-associated speck-like protein containing CARD, and Caspase-1 proteins. The findings revealed that astaxanthin significantly ameliorated mechanical and thermal pain in mice with fibromyalgia and mitigated sleep disorders and depressive-like symptoms induced by pain. A potential mechanism underlying these effects is the anti-inflammatory action of astaxanthin, likely mediated through the inhibition of the NLRP3 inflammasome, which could be one of the pathways through which astaxanthin alleviates fibromyalgia. In conclusion, our study suggests that astaxanthin holds promise as a potential analgesic medication for managing fibromyalgia and its associated symptoms.

Exercise Training Alleviates Symptoms and Cognitive Decline in a Reserpine-induced Fibromyalgia Model by Activating Hippocampal PGC-1α/FNDC5/BDNF Pathway

The purpose of this study was to assess, from a behavioral, biochemical, and molecular standpoint, how exercise training affected fibromyalgia (FM) symptoms in a reserpine-induced FM model and to look into the potential involvement of the hippocampal PGC-1α/FNDC5/BDNF pathway in this process. Reserpine (1 mg kg-1) was subcutaneously injected once daily for three consecutive days and then the rats were exercised for 21 days. Mechanical allodynia was evaluated 1, 11, and 21 days after the last injection. At the end of the exercise training protocol forced swim, open field and Morris water maze tests were performed to assess depression, locomotion and cognition, respectively. Additionally, biochemical and molecular markers related to the pathogenesis of the FM and cognitive functions were measured. Reserpine exposure was associated with a decrease in locomotion, an increase in depression, an increase in mechanical allodynia, and a decrease in spatial learning and memory (p < 0.05). These behavioral abnormalities were found to be correlated with elevated blood cytokine levels, reduced serotonin levels in the prefrontal cortex, and altered PGC-1α/FNDC5/BDNF pathway in the hippocampus (p < 0.05). Interestingly, exercise training attenuated all the neuropathological changes mentioned above (p < 0.05). These results imply that exercise training restored behavioral, biochemical, and molecular changes against reserpine-induced FM-like symptoms in rats, hence mitigating the behavioral abnormalities linked to pain, depression, and cognitive functioning.

Diosmetin attenuates fibromyalgia-like symptoms in a reserpine-induced model in mice

Fibromyalgia is a potentially disabling idiopathic disease characterized by widespread chronic pain associated with comorbidities such as fatigue, anxiety, and depression. Current therapeutic approaches present adverse effects that limit adherence to therapy. Diosmetin, an aglycone of the flavonoid glycoside diosmin found in citrus fruits and the leaves of Olea europaea L., has antinociceptive, anti-inflammatory, and antioxidant properties. Here, we investigated the effect of diosmetin on nociceptive behaviors and comorbidities in an experimental fibromyalgia model induced by reserpine in mice. To induce the experimental fibromyalgia model, a protocol of subcutaneous injections of reserpine (1 mg/kg) was used once a day for three consecutive days in adult male Swiss mice. Mice received oral diosmetin on the fourth day after the first reserpine injection. Nociceptive (mechanical allodynia, muscle strength, and thermal hyperalgesia) and comorbid (depressive-like and anxiety behavior) parameters were evaluated. Potential adverse effects associated with diosmetin plus reserpine (locomotor alteration, cataleptic behavior, and body weight and temperature changes) were also evaluated. Oral diosmetin (0.015-1.5 mg/kg) reduced the mechanical allodynia, thermal hyperalgesia, and loss of muscle strength induced by reserpine. Diosmetin (0.15 mg/kg) also attenuated depressive-like and anxiety behaviors without causing locomotor alteration, cataleptic behavior, and alteration in weight and body temperature of mice. Overall, diosmetin can be an effective and safe therapeutic alternative to treat fibromyalgia symptoms, such as pain, depression and anxiety.

Nociplastic pain mechanisms and toll-like receptors as promising targets for its management

ABSTRACT

Nociplastic pain, characterized by abnormal pain processing without an identifiable organic cause, affects a significant portion of the global population. Unfortunately, current pharmacological treatments for this condition often prove ineffective, prompting the need to explore new potential targets for inducing analgesic effects in patients with nociplastic pain. In this context, toll-like receptors (TLRs), known for their role in the immune response to infections, represent promising opportunities for pharmacological intervention because they play a relevant role in both the development and maintenance of pain. Although TLRs have been extensively studied in neuropathic and inflammatory pain, their specific contributions to nociplastic pain remain less clear, demanding further investigation. This review consolidates current evidence on the connection between TLRs and nociplastic pain, with a specific focus on prevalent conditions like fibromyalgia, stress-induced pain, sleep deprivation-related pain, and irritable bowel syndrome. In addition, we explore the association between nociplastic pain and psychiatric comorbidities, proposing that modulating TLRs can potentially alleviate both pain syndromes and related psychiatric disorders. Finally, we discuss the potential sex differences in TLR signaling, considering the higher prevalence of nociplastic pain among women. Altogether, this review aims to shed light on nociplastic pain, its underlying mechanisms, and its intriguing relationship with TLR signaling pathways, ultimately framing the potential therapeutic role of TLRs in addressing this challenging condition.

The Fibromyalgia Pain Experience: A Scoping Review of the Preclinical Evidence for Replication and Treatment of the Affective and Cognitive Pain Dimensions

Fibromyalgia is a chronic, widespread pain disorder that is strongly represented across the affective and cognitive dimensions of pain, given that the underlying pathophysiology of the disorder is yet to be identified. These affective and cognitive deficits are crucial to understanding and treating the fibromyalgia pain experience as a whole but replicating this multidimensionality on a preclinical level is challenging. To understand the underlying mechanisms, animal models are used. In this scoping review, we evaluate the current primary animal models of fibromyalgia regarding their translational relevance within the affective and cognitive pain realms, as well as summarize treatments that have been identified preclinically for attenuating these deficits.

Imperatorin inhibits oxidative stress injury and neuroinflammation via the PI3K/AKT signaling pathway in the MPTP-induced Parkinson's disease mouse

Parkinson's disease (PD) is a disorder of neurodegeneration. Imperatorin is an active natural furocoumarin characterized by antioxidant, anti-inflammatory, and potent vasodilatory properties. Therefore, we aimed to investigate the biological functions of imperatorin and its mechanisms against PD progression. C57BL/6 mice were intraperitoneally injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 30 mg/kg) daily for 5 consecutive days to mimic PD conditions in vivo. The MPTP-induced PD model mice were intraperitoneally injected with imperatorin (5 mg/kg) for 25 consecutive days after MPTP administration. The motor and cognitive functions of mice were examined by rotarod test, hanging test, narrow beam test and Morris water maze test. After analysis of MWM test, the expression levels of tyrosine hydroxylase and Iba-1 in the substantia nigra pars compacta were measured by immunohistochemistry staining, immunofluorescence staining and western blotting. The expression levels of striatal dopamine and its metabolite 3,4-dihydroxyphenylacetic acid were also measured. The protein levels of inducible nitric-oxide synthase, cyclooxygenase-2, phosphorylated phosphatidylinositol 3-kinase (PI3K) and phosphorylated protein kinase B (Akt) in the mouse striatum were estimated by western blotting. The expression levels of proinflammatory cytokines including tumor necrosis factor, interleukin (IL)-1β and IL-6 in the mouse striatum were measured by ELISA kits. The expression levels of superoxide dismutase, malondialdehyde and glutathione in the mouse midbrains were measured with commercially available kits. TUNEL staining was performed to identify the apoptosis of midbrain cells. Histopathologic changes in the mouse striata were assessed by hematoxylin-eosin staining. Imperatorin treatment markedly improved spatial learning and memory abilities of MPTP-induced PD mice. The MPTP-induced dopaminergic neuron loss in the mouse striata was inhibited by imperatorin. Imperatorin also suppressed neuroinflammation and neuronal oxidative stress in the midbrains of MPTP-induced PD mice. Mechanistically, imperatorin treatment inhibited the MPTP-induced reduction in the PI3K/Akt pathway. Imperatorin treatment can prevent dopaminergic neuron degeneration and improve cognitive functions via its potent antioxidant and anti-inflammatory properties in an MPTP-induced PD model in mice by regulating the PI3K/Akt pathway.

Pharmacokinetic differences in nicotine and nicotine salts mediate reinforcement-related behavior: an animal model study

Since their introduction in the United States and Europe in 2007, electronic cigarettes (E-Cigs) have become increasingly popular among smokers. Nicotine, a key component in both tobacco and e-cigarettes, can exist in two forms: nicotine-freebase (FBN) and nicotine salts (NS). While nicotine salt is becoming more popular in e-cigarettes, the effect of nicotine salts on reinforcement-related behaviors remains poorly understood. This study aimed to compare the reinforcing effects of nicotine and nicotine salts in animal models of drug self-administration and explore potential mechanisms that may contribute to these differences. The results demonstrated that three nicotine salts (nicotine benzoate, nicotine lactate, and nicotine tartrate) resulted in greater reinforcement-related behaviors in rats compared to nicotine-freebase. Moreover, withdrawal-induced anxiety symptoms were lower in the three nicotine salt groups than in the nicotine-freebase group. The study suggested that differences in the pharmacokinetics of nicotine-freebase and nicotine salts in vivo may explain the observed behavioral differences. Overall, this study provides valuable insights into the reinforcing effects of nicotine as well as potential differences between nicotine-freebase and nicotine salts.

Antidepressant effects of coumarins and their derivatives: A critical analysis of research advances

Coumarins and their derivatives are non-flavonoids polyphenols with diverse pharmacological activities including anti-depressant effects. This study systematically examines the antidepressant effects of coumarins and their derivatives in relation to time series of research progress in the pharmacological pathways, association with other diseases, toxicity and bibliometric analysis. The review was approached using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) coupled with R package involving Biblioshiny, a web interface for Bibliometrix analysis and VOSviewer software analytic tools. Literature searches were conducted in Scopus, Web of Science, and PubMed from the inception through January 21, 2023. Coumarins, depression, coumarin derivatives and treatment were the main search terms used which resulted in the inclusion of 46 eligible publications. Scopoletin, psoralen, 7-hydroxycoumarin, meranzin hydrate, osthole, esculetin/umbelliferone were the most studied coumarins with antidepressant effects. Coumarins and their derivatives exerted antidepressant effects with a stronger affinity for monoamine oxidase-B (MAO-B) inhibition and, their inhibitory effect via neurotransmitter pathway on MAO is well-studied. However, epigenetic modification, neuroendocrine, neurotrophic pathways are understudied. Recent research focuses on their antidepressant effects which targeted cytokines and fibromyalgia. There is a link between the gut microbiome, the brain, and depression; meranzin hydrate exerts an antidepressant activity by remodelling the gastrointestinal system. We established that empirical data on some coumarins and their derivatives to support their antidepressant effects are limited. Likewise, the safe dose range for several coumarins and their derivatives is yet to be fully determined.

The immunomodulatory effects of ethosuximide and sodium butyrate on experimentally induced fibromyalgia: The interaction between IL-4, synaptophysin, and TGF-β1/NF-κB signaling

BACKGROUND AND AIMS

Fibromyalgia is a widespread chronic pain syndrome associated with several comorbid conditions that affect the quality of patients' life. Its pathogenesis is complex, and the treatment strategies are limited by partial efficacy and potential adverse effects. So, our aim was to investigate the possible ameliorative effects of ethosuximide and sodium butyrate on fibromyalgia and compare their effects to pregabalin.

MATERIALS AND METHODS

In a mouse model of reserpine induced fibromyalgia, the effect of ethosuximide, sodium butyrate, and pregabalin was investigated. Evaluation of mechanical allodynia, cold hypersensitivity, anxiety, cognitive impairment, and depression was performed. Also, the brain and spinal cord tissue serotonin, dopamine and glutamate in addition to the serum levels of interleukin (IL)-4 and transforming growth factor beta 1 (TGF-β1) were assayed. Moreover, the expression of nuclear factor kappa B (NF-κB) synaptophysin was immunoassayed in the hippocampal tissues.

KEY FINDINGS

Ethosuximide and sodium butyrate restored the behavioral tests to the normal values except for the antidepressant effect which was evident only with ethosuximide. Both drugs elevated the levels of the anti-inflammatory cytokines IL-4 and TGF-β1, reduced the hippocampal NF-κB, and increased synaptophysin expression with superiority of sodium butyrate. Ethosuximide reduced only spinal cord and brain glutamate while improved brain dopamine while sodium butyrate elevated spinal cord dopamine and serotonin with no effect on glutamate. Also, sodium butyrate elevated brain serotonin and reduced glutamate with no effect on brain dopamine.

SIGNIFICANCE

Each of sodium butyrate and ethosuximide would serve as a promising therapeutic modality for management of fibromyalgia and its comorbid conditions.

Cannabinoids and the endocannabinoid system in fibromyalgia: A review of preclinical and clinical research

Characterised by chronic widespread musculoskeletal pain, generalised hyperalgesia, and psychological distress, fibromyalgia (FM) is a significant unmet clinical need. The endogenous cannabinoid system plays an important role in modulating both pain and the stress response. Here, we appraise the evidence, from preclinical and clinical studies, for a role of the endocannabinoid system in FM and the therapeutic potential of targeting the endocannabinoid system. While many animal models have been used to study FM, the reserpine-induced myalgia model has emerged as perhaps the most translatable to the clinical phenotype. Inhibition of fatty acid amide hydrolase (FAAH) has shown promise in preclinical studies, ameliorating pain- and anxiety-related behaviour . Clinically, there is evidence for alterations in the endocannabinoid system in patients with FM, including single nucleotide polymorphisms and increased levels of circulating endocannabinoids and related N-acylethanolamines. Single entity cannabinoids, cannabis, and cannabis-based medicines in patients with FM show promise therapeutically but limitations in methodology and lack of longitudinal studies to assess efficacy and tolerability preclude the current recommendation for their use in patients with FM. Gaps in the literature that warrant further investigation are discussed, particularly the need for further development of animal models with high validity for the multifaceted nature of FM, balanced studies to eliminate sex-bias in preclinical research, and ultimately, better translation between preclinical and clinical research.

Ambient NO2 exposure induces migraine in rats: Evidence, mechanisms and interventions

Migraine is a complex neurological disorder with a high disability rate. Although the precipitating factors of migraine remain unclear, previous studies suggest that when there is excess nitrogen dioxide (NO₂) pollution in the atmosphere, the medical demand due to migraine attacks increases sharply. However, the main role of NO₂ as a trigger for migraine is not yet well understood. The purpose of this study was to explore the relationship between NO₂ exposure and the occurrence of migraine as well as the possible underlying mechanisms. We first investigated whether repeated short-term NO₂ exposure could induce behavioural and biological migraine phenotypes in rats. Next, capsazepine (CZP) was used to block transient receptor potential cation channel subfamily V member 1 (TRPV1) in vivo, and CZP and vitamin E (VE) were used to verify the role of reactive oxygen species (ROS)-TRPV1 signalling in NO₂-induced migraine in primary trigeminal neurones in vitro. We demonstrated that short-term repeated NO₂ exposure can significantly induce migraine in rats, and its key molecular mechanism may be related to ROS burst and its downstream TRPV1 channel activation. The findings of this study will enhance the understanding of the neurotoxic mechanism of NO₂, provide new clues for identifying the aetiology of migraine, and lay a new experimental basis for implementing migraine-related preventive and therapeutic control measures.

Broad-spectrum cannabis oil ameliorates reserpine-induced fibromyalgia model in mice

Fibromyalgia (FM) is an idiopathic disorder characterized by generalized pain and associated symptoms such as depression and anxiety. Cannabis sativa shows different pharmacological activities, such as analgesic, anti-inflammatory, neuroprotective, and immunomodulatory. Associated with this, the use of an oil with low concentrations of THC can reduce the psychomimetic adverse effects of the plant. Therefore, the present study aimed to evaluate the analgesic effect of broad-spectrum cannabis oil with low THC concentration in an experimental model of FM. Mechanical hyperalgesia, thermal allodynia, depressive- and anxious-related behavior, and locomotor activity were evaluated after reserpine (0.25 mg/kg; injected subcutaneously (s.c.) once daily for three consecutive days) administration. Our results showed that oral administration of broad-spectrum cannabis oil (0.1, 1, and 3 mg/kg, p.o.) in a single dose on the 4th day inhibited mechanical hyperalgesia and thermal allodynia induced by reserpine. Relevantly, treatment during four days with broad-spectrum cannabis oil (0.1 mg/kg, p.o.) reduced mechanical hyperalgesia 1 h after reserpine administration. Intraplantar treatment with cannabis oil significantly reversed mechanical and heat thermal nociception induced by reserpine injection. Interestingly, spinal and supraspinal administration of broad-spectrum cannabis oil completely inhibited mechanical hyperalgesia and thermal sensitivity induced by reserpine. The repeated cannabis oil administration, given daily for 14 days, markedly mitigated the mechanical and thermal sensitivity during the FM model, and its reduced depressive-like behavior induced by reserpine. In summary, broad-spectrum cannabis oil is an effective alternative to reverse the reserpine-induced fibromyalgia model.

Therapeutic Approaches to Nociplastic Pain Based on Findings in the Reserpine-Induced Fibromyalgia-Like Animal Model

Nociplastic pain, the third category of chronic pain, has emerged as a serious medical issue. Due to its significant negative influences on patients and society, high prevalence, and lack of sufficiently effective treatments, more efficacious therapies are required. This review highlights the potential therapeutic approaches identified in studies that used reserpine-induced myalgia (RIM) animal model that exhibits nociplastic pain-associated phenotypes. These studies have revealed that biological processes including the chronic reduction of monoamines, increase of oxidative/nitrosative stresses and inflammatory mediators, upregulation of pronociceptive neurotransmitters and their receptors, increase of trophic factors, enhancement of the apoptotic pathway, sensory nerve sensitization, and activation of immune cells in central and/or peripheral regions, underly the nociplastic pain-associated phenotypes in RIM animal model. Potential therapeutic approaches to nociplastic pain, i.e., 1) functional modification of specific molecules which expression is distinctly altered following monoamine reduction, 2) targeting the molecules which are responsible for other major categories of chronic pain (i.e., chronic inflammatory pain and neuropathic pain), 3) supplementation of nutrition to correct the disrupted nutritional balance, 4) improvement of physical constitution by natural substances, and 5) nonpharmacological interventions, have been identified. Significance Statement Studies in RIM animal model have revealed the pathologies that occur after the chronic reduction of monoamines and identified potential therapeutic approaches to nociplastic pain. Translation of their analgesic efficacy from RIM animal model to patients remains an issue to be addressed. Successful translation would lead to better therapies for nociplastic pain.

Role of Different Doses of Ketamine in Postoperative Neurocognitive Function in Aged Mice Undergoing Partial Hepatectomy by Regulating the Bmal1/NMDA/NF-Κb Axis

BACKGROUND

The current study set out to probe the function of different doses of ketamine in postoperative neurocognitive disorder (PND) in aged mice undergoing partial hepatectomy (PH) with the involvement of the brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 (Bmal1)/n-methyl-D-aspartate (NMDA)/nuclear factor-kappa B (NF-κB) axis.

METHODS

First, aged mice were intraperitoneally injected with different doses of ketamine prior to surgery, followed by hepatic lobectomy. Afterward, mice cognitive function was assessed. In addition, Bmal1 mRNA expression patterns were quantified, while NMDA 2B receptor, NF-κB p65, synapsin 1, and postsynaptic density 95 (PSD95) levels were determined; the release of inflammatory factors was detected, and ionized calcium-binding adapter molecule-1 expression was measured to quantify microglia activation. In addition, Bmal1-knockout (Bmal1-KO) mice were intraperitoneally injected with a subanesthetic dose of ketamine to verify the mechanism of Bmal1 in regulating the NMDA 2B subunit (NR2B)/NF-κB axis to affect PH in aged patients.

RESULTS

After PH, hippocampal-dependent memory was impaired, and synapsin 1 and PSD95 levels were downregulated. On the other hand, PH diminished Bmal1 expression but elevated NR2B and NF-κB p65 levels and anesthetic doses of ketamine further regulated the Bmal1/NMDA/NF-κB axis. In Bmal1-KO mice, the NMDA/NF-κB axis was activated, the release of inflammatory cytokines was promoted, and hippocampus-dependent memory was impaired, which were reversed by a subanesthetic dose of ketamine.

CONCLUSION

Altogether, findings obtained in our study indicated that a subanesthetic dose of ketamine activated Bmal1, downregulated the NMDA/NF-κB axis, and reduced inflammation and microglia activation to alleviate PND in aged mice undergoing PH.

Understanding the phytochemistry and molecular insights to the pharmacology of Angelica archangelica L. (garden angelica) and its bioactive components

Plant-derived molecules have enduring usefulness in treating diseases, and herbal drugs have emerged as a vital component of global therapeutic demand. Angelica archangelica L. (A. archangelica), commonly known as garden angelica, is an aromatic food plant used in culinary procedures as a flavoring agent. In the traditional medicine system, it is regarded as an "Angel plant" due to its miraculous curative power. This review aims to provide a comprehensive summary of the plant's taxonomic profile, ethnopharmacology, Phytochemistry, and pharmacological activities. Various in vivo and in vitro experiments have validated that the plant possesses broad pharmacological potential. The biological activities attributed to the plant include anti-anxiety activity, anti-convulsant activity, cognition enhancer, antiviral activity, cholinesterase inhibitory potential, antiinflammatory activity, gastroprotective activity, and radioprotective activity. The beneficial effects of the plant are credited to its bioactive components, that is, coumarins and volatile oils. The review summarizes the pharmacological activities of crude extract and its bioactive fractions and has also explored their target-oriented effects. This review will be of value in undertaking further investigations on the plant with regard to exploring mechanism-based pharmacological approaches on A. archangelica.

Animal models of fibromyalgia: What is the best choice?

Fibromyalgia (FM) is a complex syndrome, with an indefinite aetiology and intricate pathophysiology that affects 2 - 3% of the world population. From the beginning of the 2000s, experimental animal models have been developed to mimic clinical FM and help obtain a better understanding of the relevant neurobiology. These animal models have enabled a broad study of FM symptoms and mechanisms, as well as new treatment strategies. Current experimental FM models include the reserpine-induced systemic depletion of biogenic amines, muscle application of acid saline, and stress-based (cold, sound, or swim) approaches, among other emerging models. FM models should: (i) mimic the cardinal symptoms and complaints reported by FM patients (e.g., spontaneous nociception, muscle pain, hypersensitivity); (ii) mimic primary comorbidities that can aggravate quality of life and lead to worse outcomes (e.g., fatigue, sleep disturbance, depression, anxiety); (iii) mimic the prevalent pathological mechanisms (e.g., peripheral and central sensitization, inflammation/neuroinflammation, change in the levels of the excitatory and inhibitory neurotransmitters); and (iv) demonstrate a pharmacological profile similar to the clinical treatment of FM. However, it is difficult for any one of these models to include the entire spectrum of clinical FM features once even FM patients are highly heterogeneous. In the past six years (2015 - 2020), a wide range of experimental FM studies has amounted to the literature reinforcing the need for an updated review. Here we have described, in detail, several approaches used to experimentally study FM, with a focus on recent studies in the field and in previously less discussed mechanisms. We highlight each model's challenges, limitations, and future directions, intending to help preclinical researchers establish the correct experimental FM model to use depending on their goals.

Angelica dahurica and Rheum officinale Facilitated Diabetic Wound Healing by Elevating Vascular Endothelial Growth Factor

Traditional Chinese medicine (TCM) provides alternative treatment choices for diabetic wounds. The aim of this study was to evaluate the effects of Angelica dahurica and Rheum officinale (ARE) on diabetic wounds and its underlying action mechanism. A total of 36 healthy male Sprague-Dawley rats were randomly divided into three groups: diabetes mellitus (DM) rats treated with ARE (DM-ARE), DM rats treated with 0.9% saline (DM-NS), and non-DM rats treated with 0.9% saline (NDM-NS). DM was induced by intraperitoneal administration of 40 mg/kg of streptozotocin after a 2-week high-fat diet feeding. After excisional skin wounds and treatments, the remaining wound area (RWA) in each group was measured. The RWA in the DM-NS group (69.60% ± 2.35%) was greater than that in the DM-ARE (55.70% ± 1.85%) and NDM-NS groups (52.50% ± 2.77%) on day 6. Besides, the DM-ARE group showed higher vascular endothelial growth factor (VEGF), higher inducible nitric oxide synthase (iNOs), higher [Formula: see text]-smooth muscle actin ([Formula: see text]-SMA), and lower nuclear factor kappa-light-chain-enhancer of activated B cell (NF-[Formula: see text]B) expression in the wound skin tissue. These results showed that treatment with ARE shifted the recovery pattern of diabetic rats to the pattern of nondiabetic rats, indicating that ARE may improve wound healing in diabetic conditions.

Exercise Reduces Pain and Deleterious Histological Effects in Fibromyalgia-like Model

Fibromyalgia (FM) is characterized by chronic pain and associated comorbidities such as fatigue, anxiety, depression, and sleep disorders. There is a large amount of evidence regarding the benefits of physical exercise in controlling chronic pain. However, there is no consensus on which exercise modality is most suitable and the real benefits of this intervention to treat FM symptoms. The present study investigated the analgesic and antidepressant effects and morphophysiological responses induced by different physical exercise (aerobic and strength protocols) during the experimental model of FM. Spontaneous pain, mechanical hyperalgesia, thermal allodynia, depression-related behavior, and locomotor activity were evaluated weekly, as well as the morphological evaluation of the spinal cord and dorsal root ganglion. Aerobic and strength training protocols consistently abolished nociceptive behaviors, reducing spontaneous pain scores, cold allodynia, and frequency of response to mechanical hyperalgesia. The strength exercise modulated the depressive-like behavior. Finally, our data demonstrated that physical exercise performed for two weeks increased the number of glial cells in the dorsal root horn. However, it was not sufficient to control the other deleterious effects of the reserpine model on the spinal cord and the dorsal root. Together, these results demonstrated that different physical exercise modalities, when performed regularly in mice, proved to be effective and safe non-pharmacological alternatives for the treatment of FM. However, some gaps have yet to be studied regarding the neuroadaptive effects of physical exercise.

Serotonergic Neurotransmission System Modulator, Vortioxetine, and Dopaminergic D2/D3 Receptor Agonist, Ropinirole, Attenuate Fibromyalgia-Like Symptoms in Mice

Fibromyalgia is a disease characterized by lowered pain threshold, mood disorders, and decreased muscular strength. It results from a complex dysfunction of the nervous system and due to unknown etiology, its diagnosis, treatment, and prevention are a serious challenge for contemporary medicine. Impaired serotonergic and dopaminergic neurotransmission are regarded as key factors contributing to fibromyalgia. The present research assessed the effect of serotonergic and dopaminergic system modulators (vortioxetine and ropinirole, respectively) on the pain threshold, depressive-like behavior, anxiety, and motor functions of mice with fibromyalgia-like symptoms induced by subcutaneous reserpine (0.25 mg/kg). By depleting serotonin and dopamine in the mouse brain, reserpine induced symptoms of human fibromyalgia. Intraperitoneal administration of vortioxetine and ropinirole at the dose of 10 mg/kg alleviated tactile allodynia. At 5 and 10 mg/kg ropinirole showed antidepressant-like properties, while vortioxetine had anxiolytic-like properties. None of these drugs influenced muscle strength but reserpine reduced locomotor activity of mice. Concluding, in the mouse model of fibromyalgia vortioxetine and ropinirole markedly reduced pain. These drugs affected emotional processes of mice in a distinct manner. Hence, these two repurposed drugs should be considered as potential drug candidates for fibromyalgia. The selection of a specific drug should depend on patient’s key symptoms.

Daphnetin, a natural coumarin averts reserpine-induced fibromyalgia in mice: modulation of MAO-A

Fibromyalgia is a common, chronic, and generalized pain syndrome that is often associated with comorbid depression. The etiology of fibromyalgia is complex; most researchers have documented that the hallmark symptoms are due to the central nervous system's abnormal functioning. Neurotransmitters such as serotonin, norepinephrine, and glutamate, have been reported to be key regulators of fibromyalgia syndrome. Daphnetin is a 7, 8 dihydroxy coumarin widely distributed in Thymelaeaceae family plants, possessing various activities such as anti-arthritic, anti-tumor, anti-malarial, and anti-parasitic. The present study was designed to explore the potential of daphnetin against reserpine-induced fibromyalgia in mice. In mice, a fibromyalgia-like state was achieved by injecting reserpine (0.5 mg/kg, s.c) continuously for 3 days. All behavioral tests were conducted on the 4th and 6th day of experimentation. Reserpine administration significantly increased the mechanical hypersensitivity in electronic von Frey (eVF) and pressure application measurement (PAM) tests. It also increased the immobility period and time to reach the platform in force swim test (FST) and Morris water maze (MWM) test, respectively. In the biochemical analysis, reserpine treatment upregulated the monoamine oxidase-A (MAO-A) activity and level of glutamate, tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and thiobarbituric acid reactive substances (TBARS). Whereas, it decreased the level of glutathione (GSH), dopamine, serotonin, and norepinephrine. Daphnetin pretreatment attenuated the behavioral and biochemical changes induced by reserpine. Thus, the current investigation results delineate that daphnetin might exert its protective effect by inhibiting inflammatory stress and MAO-A-mediated neurotransmitter depletion and oxidative stress.

Imperatorin Interferes with LPS Binding to the TLR4 Co-Receptor and Activates the Nrf2 Antioxidative Pathway in RAW264.7 Murine Macrophage Cells

Imperatorin (IMP) could downregulate several inflammatory transcription factor signaling pathways. Some studies have pointed out that IMP could interfere with toll-like receptor 4 (TLR4) signaling. This study evaluates how IMP interferes with the TLR4 co-receptors signaling through the protein-ligand docking model, Western blotting, immunofluorescence (IF), and atomic force microscopy (AFM) assays in lipopolysaccharide (LPS) stimulated macrophage-like RAW264.7 cells in vitro. The results of the protein-ligand docking demonstrate that IMP interferes with LPS binding to the LPS-binding protein (LBP), the cluster of differentiation 14 (CD14), and the toll-like receptor 4/myeloid differentiation factor 2 (TLR4/MD-2) co-receptors in LPS-stimulated RAW264.7 cells. Compared with TLR4 antagonist CLI-095 or dexamethasone, IMP could suppress the protein expressions of LBP, CD14, and TLR4/MD-2 in LPS-stimulated cells. Furthermore, the three-dimensional (3D) image assay of the AFM showed IMP could prevent the LPS-induced morphological change in RAW264.7 cells. Additionally, IMP could activate the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, and it increased the antioxidative protein expression of heme oxygenase-1 (HO-1), superoxidase dismutase (SOD), and catalase (CAT). Our results are the first to reveal that the anti-inflammatory effect of IMP interferes with LPS binding to TLR4 co-receptor signaling and activates the antioxidative Nrf2 signaling pathway.

Skimmetin/osthole mitigates pain-depression dyad via inhibiting inflammatory and oxidative stress-mediated neurotransmitter dysregulation

Pain and depression are often co-existing pathological states that promote mutual severity resulting in limited efficacy of current treatment strategies. Thus, there is a need to develop an efficacious alternate treatment regimen for pain-depression dyad. Skimmetin and osthole are molecules of natural origin that have been explored for an anti-hyperglycemic, anti-bacterial, anti-fungal, and anti-diabetic activities in preclinical studies. in animal models. The current study has been designed to explore the beneficial effect of skimmetin/osthole in reserpine-induced pain-depression dyad in mice. Female Swiss albino mice (n = 6) were challenged with reserpine (0.5 mg/kg s.c.) for the first 3 days to induce a pain-depression dyad-like state. Skimmetin (10 mg/kg i.p.) and osthole (10 mg/kg i.p.) were administered for 5 days consecutively, starting from the first day of study. Reserpine treatment significantly reduced the pain threshold in the pressure application measurement (PAM) and electronic von frey (eVF) test. In forced swim test (FST) and Morris water maze (MWM) test mice displayed an increased immobility time and latency to reach platform respectively. Biochemical results showed an increased level of TNF-α, IL-1β, TBARS, glutamate, and reduced level of GSH, norepinephrine, and serotonin in the reserpine treated group. Reserpine treatment also increased brain MAO-A activity. Skimmetin/osthole treatment was found to attenuate the behavioral and biochemical alterations induced by reserpine. The results of the current investigation delineated that skimmetin/osthole may exert anti-nociceptive, anti-depressant, and improved cognition via inhibiting inflammatory and oxidative stress-mediated neurotransmitter dysregulation.

Does COVID19 activates previous chronic pain? A case series

Introduction

With the outbreak of coronavirus, the number of patients who referred to the pain clinic for follow-up was much higher than before, which coincided with the onset of the coronavirus pandemic. However, due to incomplete knowledge regarding the virus and its effects, patients did not follow up to the pain.

Methods

We present case of 8 patients who were treated previously for chronic pain (complete remission).

Results

During the pandemic, these patients were presented to our center presenting identical pain, that did not respond to the conservative therapy. Owing to the symptoms, these patients were screened and tested positive for COVID19. Two of the patients died whereas, symptoms were improved in other patients.

Conclusion

Patients with the history of chronic pain may present relapse as a result of the infection or infection can trigger previous chronic pain among patients with risk factors.

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Coronavirus disease 2019 (COVID19), caused by new coronavirus.

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Due to incomplete knowledge regarding the virus and its effects, patients did not follow up to the pain.

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Patients with the history of chronic pain may present relapse.

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Infection can trigger previous chronic pain among patients with risk factors.

Xanthotoxin affects depression-related behavior and neurotransmitters content in a sex-dependent manner in mice

The present study aimed to evaluate xanthotoxin's influence on male and female Swiss mice's depression-like behaviors and investigate the potential mechanism of this effect. Naturally derived furanocoumarin (the Apiaceae family), xanthotoxin, administered acutely (12.5 mg/kg), diminished the immobility level in the forced swim test only in males. The immobility level was lower in females than males, which may be associated with a higher serotonin level in the female prefrontal cortex. A dose-dependent increase of serotonin and noradrenaline was reported in the reverse-phase ion-pair liquid chromatography in the female prefrontal cortex but not in the hippocampus. We suggest that xanthotoxin may exert antidepressant properties and affect males and females differently. The increasing level of serotonin in the male and female prefrontal cortex may underlie this effect.

Optimization of extraction conditions of Angelica archangelica extract and activity evaluation in experimental fibromyalgia

The plant Angelica archangelica, owing to its magnificent therapeutic effectiveness in folklore medicine system, has been regarded as an "angel plant." The current investigation was aimed to optimize extraction conditions of A. archangelica roots and to investigate in vivo role of optimized extract in fibromyalgia. Plant material (dried roots) was subjected to methanol extraction at variable temperature (40 to 60 °C) and time (12 to 36 hr) conditions as per two-factorial design strategy, and responses in terms of antioxidant activity were determined. The optimized extraction conditions were found to be temperature of 60 °C and time of 36 hr. HPLC fingerprinting indicated the presence of coumarins in extract. To induce fibromyalgia, the mice were administered reserpine at a dose of 0.5 mg/kg. Mice were orally treated with 100, 200, and 400 mg/kg extract, and magnitude of fibromyalgia was quantified. In comparison to reserpine group, the extract treatment attenuated pain as shown by significant increase in paw withdrawal threshold against mechanical stimuli (P < 0.05), improved motor ability indicated by increase in fall-off time in inclined plane test (P < 0.05), improved locomotion indicated by increased square crossings in open field test (P < 0.05), and improved cognition as shown by significant reduction in time to reach platform in Morris water maze test and passive avoidance task test (P < 0.05). Extract treatment significantly halted reserpine-induced rise in serum cytokine level (P < 0.05) and brain oxidative stress (P < 0.05). Angelica archangelica extract exerted its beneficial effects in fibromyalgia possibly through the attenuation of oxidative stress-mediated inflammatory cascade. PRACTICAL APPLICATION: Leads from natural products have become an integral part of drug designing processes and have high acceptability due to their better tolerance. The optimization of extraction conditions of plant yields better results and could reduce the processing time, thus increasing its industrial value.

Involvement of Oxidative Stress and Nerve Growth Factor in Behavioral and Biochemical Deficits of Experimentally Induced Musculoskeletal Pain in Mice: Ameliorative Effects of Heraclin

Musculoskeletal pain is a widespread complex regional pain syndrome associated with altered emotional and cognitive functioning along with heightened physical disability that has become a global health concern. Effective management of this disorder and associated disabilities includes accurate diagnosis of its biomarkers and instituting mechanism-based therapeutic interventions. Herein, we explored the role of heraclin, a plant-derived molecule, in musculoskeletal pain and its underlying mechanistic approaches in an experimental mouse model. Reserpine (0.5 mg/kg) for 3 consecutive days evoked hyperalgesia, motor incoordination, lack of exploratory behavior, anxiety, and cognition lapse in mice. Reserpine-challenged mice displayed higher serum cytokine level, altered brain neurotransmitter content, elevated brain and muscle oxidative stress, and upregulated brain nerve growth factor receptor expression. Treatment with heraclin (10 mg/kg for 5 consecutive days) exerted analgesic effect and improved motor coordination and memory deficits in mice. Heraclin arrested serum cytokine rise, normalized brain neurotransmitter content, reduced tissue oxidative stress, and downregulated the nerve growth factor receptor expression. Therefore, it may be suggested that heraclin exerts beneficial effects against reserpine-induced musculoskeletal pain disorder possibly through the attenuation of NGFR-mediated pain and inflammatory signaling. Graphical Abstract.

In Silico Studies and In Vivo MAOA Inhibitory Activity of Coumarins Isolated from Angelica archangelica Extract: An Approach toward Antidepressant Activity

The current investigation was aimed at in vivo MAO_A inhibitory activity of coumarins angelicin, bergapten, and scopoletin isolated from the roots of Angelica archangelica. The isolated compounds were screened for MAO_A (pdb ID 2Z5y) binding through molecular docking studies. The molecular docking results displayed that bergapten has a maximum affinity for MAO_A, followed by angelicin and scopoletin. In silico prediction of physicochemical parameters indicated that maximum blood-brain barrier (BBB) permeability was observed with angelicin (2.3), followed by bergapten (2.0) and least with scopoletin (0.644). In consonance to the results of molecular docking studies, appreciable in vivo antidepressant activity of angelicin and bergaptan was observed over the mouse model of reserpine-induced depression. The modulation of MAO_A in the antidepressant effect of extract and its isolated fractions was also determined. Biochemical examination of the brain tissue indicated that bergapten has maximum MAO_A inhibitory activity while scopoletin fails to inhibit brain MAO_A.

Wnt3a Inhibitor Attenuates Remifentanil-Induced Hyperalgesia via Downregulating Spinal NMDA Receptor in Rats

Purpose

The upregulation of spinal NMDA receptor is a crucial mechanism in remifentanil-induced hyperalgesia (RIH). Wnt3a/β-catenin pathway plays an important role in neuropathic pain. We hypothesized that wnt3a inhibitor (iwp-2) could downregulate the expression of NR₂B subunit in NMDA receptor, in order to relieve RIH.

Materials and Methods

The study has 2 phases. The phase 1 study is designed by different doses of iwp-2 groups to create an appropriate iwp-2 dose used in RIH alleviation. The phase 2 study is designed to prove that the wnt3a inhibitor could downregulate the activation of the NR₂B to inhibit RIH in rats. Thermal hyperalgesia (PWTL) and mechanical allodynia (PWMT) were evaluated after RIH. The area under the PWTL and PWMT curves (AUC) were calculated. The amount of activated NR₂B subunit, c-fos, NF-κB, β-catenin, wnt3a and p-GSK-3β (Ser9) were detected in the lumbar spinal cord.

Results

Remifentanil infusion could induce overexpression of β-catenin and wnt3a in rats. Iwp-2 (60μM, 120μM, 180μM) could dose-dependently inhibit thermal hyperalgesia and mechanical allodynia in rats. In phase 2 study, both NR₂B subunit antagonist Ro25-6981 and iwp-2 decreased the amount of activated NR₂B, enhanced p-GSK-3β (Ser9), reduced β-catenin, c-fos and NF-κB in the lumbar spinal cord (p < 0.001). In comparison with the group iwp-2, the group of Ro25-6981 had more benefit in reversing hyperalgesia, including higher AUC value of PWTL (p = 0.022) and PWMT (p = 0.035).

Conclusion

Remifentanil exposure could induce overexpression of wnt3a and enhance the production of β-catenin in the spinal dorsal horn. Inhibition of wnt3a response was capable of attenuating RIH in alleviating hyperalgesia-related behavioral parameters, as well as reducing overexpression of c-fos, NF-κB, NR₂B in spinal dorsal horn.

Imperatorin: A review of its pharmacology, toxicity and pharmacokinetics

As a naturally occurring furanocoumarin, the medicinal value of imperatorin has been studied more and more. We hope to provide useful information for the further development of imperatorin by analyzing the literature of imperatorin in recent years. By collating the literature on the pharmacology of imperatorin, we found that the pharmacological activity of imperatorin is wide and imperatorin can be used for anti-cancer, neuroprotection, anti-inflammatory, anti-hypertension and antibacterial. In addition, we found that some researchers confirmed the toxicity of imperatorin. Pharmacokinetic studies demonstrated that oxidation metabolism is the main metabolic pathways of imperatorin. At present, the shortcomings of research on imperatorin mainly include: most pharmacological studies are concentrated in vitro, lacking enough in vivo experimental data; more and more studies showed that imperatorin has synergistic effect with other drugs in anticancer and other aspects, but lacking the detailed explanation of the mechanism of the synergistic effect; imperatorin has side effect, but it lacks enough experimental conclusions. Based on the above defects, we believe that more in vivo experiments of imperatorin should be carried out in the future; future research need to explore synergistic mechanisms of imperatorin with other drugs, especially in anticancer; the dose affects both the pharmacological activity and the side effect of imperatorin. The relationship between the dose and the two aspects need to be further studied in order to reduce the side effect. In addition, through structural modification of imperatorin, it is possible to improve the treatment effect and reduce side effect.

Nelumbo nucifera Gaertn Stems (Hegeng) Improved Depression Behavior in CUMS Mice by Regulating NCAM and GAP-43 Expression

Background

Nelumbo nucifera Gaertn stem (Hegeng [HG]) is a traditional Chinese medicine that is used to treat mental symptoms in East Asia. However, scientific evidence is generally lacking to support this traditional claim. Aim of the Study. This study's aim is to investigate the antidepression effect of HG and to further explore the possible molecular mechanisms that are involved in its actions. Materials and Methods. HG aqueous extract was administered intragastrically for 21 days after the chronic unpredictable mild stress (CUMS) procedure, and its effect on memory, learning, and emotion was assessed using animal behavioral tests. HG aqueous extract was characterized using HPLC. Immunofluorescence was used to measure the neural cell-adhesion molecule (NCAM) and growth-associated protein-43 (GAP-43) expression.

Results

Depression-like behaviors increased in the CUMS group compared with the control (CON) group, while they were reduced in the high-dose HG (H-HG) and fluoxetine (FLU) groups (p < 0.05). Additionally, NCAM and GAP-43 expression was reduced in the CUMS group compared with the CON group, but it increased in the H-HG and FLU groups (p < 0.05).

Conclusions

These findings show the potential antidepressant effects of HG through mechanisms involving regulation of NCAM and GAP-43. This provides a new theoretical basis for its potential application as an antidepressant-like agent.

Simultaneous Determination of Three Coumarins in Angelica dahurica by 1H-qNMR Method: A Fast and Validated Method for Crude Drug Quality Control

In this study, a quantitative ¹H NMR method (¹H-qNMR) for determining the contents of imperatorin, byakangelicin, and oxypeucedanin in A. dahurica in traditional Chinese medicine (TCM) has been established. Dried plant material was extracted exhaustively with methanol by an ultrasonication-assisted extraction method. The ¹H-qNMR measurements were performed on a 600 -MHz spectrometer with hydroquinone as the internal standard reference in deuterated dimethyl sulfoxide (DMSO-d₆) solvent. Quantification was carried out using the ¹H resonance signals at 6.55 ppm for hydroquinone and 7.68, 7.38-7.39, and 6.38-6.39 ppm for imperatorin, byakangelicin, and oxypeucedanin, respectively. The linearity, limit of detection (LOD), limit of quantitation (LOQ), precision, reproducibility, stability, and recovery of the methodology were evaluated, and results were good. The newly developed method has been applied to determine the three coumarins in A. dahurica.