Analgesic Activity of Catalpol in Rodent Models of Neuropathic Pain, and Its Spinal Mechanism

Exploring the Therapeutic Potential of Mesenchymal Stem Cells-derived conditioned medium: An In-depth Analysis of Pain Alleviation, Spinal CCL2 Levels, and Oxidative Stress

Neuropathic pain, a debilitating condition, remains a significant challenge due to the lack of effective therapeutic solutions. This study aimed to evaluate the potential of mesenchymal stromal cell (MSC)-derived conditioned medium in alleviating neuropathic pain induced by sciatic nerve compression injury in adult male rats. Forty Wistar rats were randomly assigned to four groups: control, nerve injury, nerve injury with intra-neural injection of conditioned medium, and nerve injury with intra-neural injection of culture medium. Following sciatic nerve compression, the respective groups received either 10 µl of conditioned medium from amniotic fluid-derived stem cells or an equal volume of control culture medium. Behavioral tests for cold allodynia, mechanical allodynia, and thermal hyperalgesia were conducted, and the spinal cord was analyzed using Western Blot and oxidative stress assays. The behavioral experiments showed a decrease in mechanical hyperalgesia and cold allodynia in the group receiving conditioned medium compared to the injury group and the control medium group. Western blot data revealed a decrease in the expression of the CCL2 protein and an increase in GAD65. Oxidative stress tests also showed increased levels of SOD and glutathione in conditioned media-treated animals compared to animals with nerve injury. The findings suggest that conditioned medium derived from amniotic fluid-derived stem cells can effectively reduce neuropathic pain, potentially through the provision of supportive factors that mitigate oxidative stress and inflammation in the spinal cord.

Catalpol ameliorates CFA-induced inflammatory pain by targeting spinal cord and peripheral inflammation

Chronic, inflammatory pain is an international health concern that severely diminishes individuals' quality of life. Catalpol is an iridoid glycoside derived from the roots of Rehmannia glutinosa that possesses anti-inflammatory, antioxidant, and neuroprotective properties for the treating multiple kinds of disorders. Nevertheless, catalpol's impacts on inflammatory pain and its potential methods of action are still unclear. The purpose of this investigation is to determine the mechanism of catalpol to reduce the inflammatory pain behaviors in a rat model with complete Freund's adjuvant (CFA). Catwalk, Von-Frey, and open field testing were performed for behavioral assessment. Western blot analysis and real-time quantitative PCR (RT-PCR) were employed to identify variations in molecular expression, while immunofluorescence was utilized to identify cellular localization. Catalpol effectively reduced CFA-induced mechanical allodynia and thermal hyperalgesia when injected intrathecally. Moreover, catalpol can regulate the HDAC4/PPAR-γ-signaling pathway in CFA rat spinal cord neurons. Meanwhile catalpol significantly decreased the expression of the NF-κB/NLRP3 inflammatory axis in the spinal cord of CFA rats. In addition, both in vivo and in vitro research revealed that catalpol treatment inhibited astrocyte activation and increase inflammatory factor expression. Interestingly, we also found that catalpol could alleviate peripheral pain by inhibiting tissue inflammation. Taken together, the findings declared that catalpol may inhibit inflammatory pain in CFA rats by targeting spinal cord and peripheral inflammation.

Therapeutic potential of catalpol and geniposide in Alzheimer's and Parkinson's diseases: A snapshot of their underlying mechanisms

Rehmannia glutinosa, the fresh or dried root of Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & Mey., and Gardenia, the fruit of Gardenia jasminoides Ellis from Rubiaceae, both are famous traditional Chinese medicines that have been traditionally used in China. Catalpol and geniposide, as two kinds of iridoid glycosides with high activities, are the main bioactive components in Rehmannia glutinosa and Gardenia jasminoides Ellis, respectively. Over the past few decades, catalpol and geniposide have been widely studied for their therapeutic effects. The preclinical experiments demonstrated that they possessed significant neuroprotective activities against Alzheimer's disease, Parkinson's disease, stroke, and depression, etc. In this paper, the pharmacological effects and mechanisms of catalpol and geniposide on Alzheimer's disease and Parkinson's disease from 2005 to now were systematically summarized and comprehensively analyzed. At the same time, the pharmacokinetic characteristics of the analyzed compounds were also described, hoping to provide some enlightenment for the design, research, and development of iridoid glycosides.

Catalpol Protects Against Spinal Cord Injury in Mice Through Regulating MicroRNA-142-Mediated HMGB1/TLR4/NF-κB Signaling Pathway

Background: Spinal cord injury (SCI) is a devastating condition that leads to paralysis, disability and even death in severe cases. Inflammation, apoptosis and oxidative stress in neurons are key pathogenic processes in SCI. Catalpol (CTP), an iridoid glycoside extracted from Rehmannia glutinosa, has many pharmacological activities, such as anti-inflammatory, anti-oxidative and anti-apoptotic properties.

Purpose: Here, we investigated whether CTP could exert neuroprotective effects against SCI, and explored the underlying mechanism involved.

Methods: SCI was induced by a weight-drop device and treated with CTP (10 mg and 60 mg/kg). Then the locomotor function of SCI mice was evaluated by the BBB scores, spinal cord edema was measured by the wet/dry weight method, oxidative stress markers and inflammatory factors were detected by commercial kits and neuronal death was measured by TUNEL staining. Moreover, the microRNA expression profile in spinal cords from mice following SCI was analyzed using miRNA microarray. In addition, reactive oxygen species (ROS) generation, inflammatory response and cell apoptosis were detected in murine microglia BV2 cells under oxygen-glucose deprivation (OGD) and CTPtreatment.

Results: Our data showed that CTP treatment could improve the functional recovery, as well as suppress the apoptosis, alleviate inflammatory and oxidative response in SCI mice. In addition, CTP was found to be up-regulated miR-142 and the protective effects of CTP on apoptosis, inflammatory and oxidative response may relate to its regulation of HMGB1/TLR4/NF-κB pathway through miR-142.

Conclusion: Our findings suggest that CTP may protect the spinal cord from SCI by suppression of apoptosis, oxidative stress and inflammatory response via miR-142/HMGB1/TLR4/NF-κB pathway.

Ninjin'yoeito Alleviates Neuropathic Pain Induced by Chronic Constriction Injury in Rats

Kampo medicines are frequently used empirically to treat pain in clinical practice. Ninjin'yoeito (NYT), which is associated with few adverse effects, is often used to treat the elderly, but has not yet been examined in detail. We herein investigated the effects of NYT, at 500 and 1,000 mg/kg p.o. (NYT500/NYT1000 group) in single and repeated administrations for 14 days, on pain in rats with peripheral neuropathy induced by loose ligation of the sciatic nerve (chronic constriction injury: CCI). Untreated CCI rats given distilled water were used as a control group. To assess induced pain, the pain threshold was measured using the von Frey test. To evaluate spontaneous pain, the ground-contact area of the paw with neuropathic pain was measured using the Dynamic Weight Bearing test. Serum samples were collected after the test to elucidate the mechanism of action of NYT, and brain-derived neurotrophic factor (BDNF) and corticosterone protein levels, which have been reported to change due to chronic pain, were analyzed. After single administration of NYT, the pain threshold rose in the NYT500 and NYT1000 groups. The pain threshold tended to rise on day 14 of repeated administration in the NYT500 group (p = 0.08) and it significantly rose at NYT1000 group (p < 0.05) compared to Control group. In addition, the foot contact area increased (p = 0.09). Therefore, CCI-induced pain was significantly remitted and spontaneous pain was remitted after repeated administration of NYT. Serum BDNF levels were higher in untreated CCI rats than in normal rats (p = 0.05), but decreased after the repeated administration of NYT (NYT1000, p = 0.15), while serum corticosterone levels were lower (p = 0.12) than those in normal rats and increased after the repeated administration of NYT (NYT1000, p = 0.07). The blood BDNF level has been suggested to influence pain intensity. The findings demonstrated NYT effectively treats neuropathic pain, suggesting that a NYT-induced decrease in blood BDNF contributed to the mechanism of pain relief. In addition, the variation of corticosterone was observed, suggesting that normalization of responsiveness to stress by NYT contributed to the pain relief.

Iridoids isolated from Viticis Fructus inhibit paclitaxel-induced mechanical allodynia in mice

Chemotherapy-induced peripheral neuropathy (CIPN) manifests as mechanical allodynia and hyperalgesia, and is one of the main adverse effects of chemotherapeutic agents. Currently available therapeutic drugs are not sufficiently effective for the management of this adverse effect in the clinic. Therefore, the development of novel therapeutic agents for treating CIPN is necessary. Our previous study suggested the potential of aucubin and pedicularis-lactone (1) as active compounds responsible for the anti-allodynic property of Plantaginis Semen. However, the activity of purified 1 has not been evaluated due to its low content in Plantaginis Semen. In the present study, 1 was isolated from Viticis Fructus, as well as viteoid I (2) and viteoid II (3) during the process of isolation. The purities of isolated 1, 2, and 3 were determined as 67.15%, 92.12%, and 86.72%, respectively, by quantitative ¹H-NMR, using DSS-d₆ as an internal standard. Repeated daily oral administration of these three iridoids at a dose of 15 mg/kg significantly inhibited the PTX-induced mechanical allodynia in mice, suggesting the anti-allodynic activities of 1, 2, and 3. This study provides confirmatory evidence for the anti-allodynic activity of purified 1 and also reveals two additional active iridoids from Viticis Fructus. These three iridoids could be potential candidates for the treatment of CIPN.

Efficacy, safety, and cost-effectiveness analysis of adjuvant herbal medicine treatment, Palmijihwang-hwan, for chronic low back pain: a study protocol for randomized, controlled, assessor-blinded, multicenter clinical trial

Background

Low back pain is a common symptom and continuous or recurrent pain results in chronic low back pain (CLBP). While many patients with CLBP have tried various treatments, complementary and alternative medicine including acupuncture and herbal medicine is one of the commonly used treatments. Palmijihwang-hwan is a herbal medicine used frequently in clinical practice but there has been no report of the efficacy, safety, or cost-effectiveness analysis of Palmijihwang-hwan for CLBP.

Methods

This study is a randomized, assessor-blinded, multicenter, clinical trial with two parallel groups. Four Korean medicine hospitals will recruit 84 participants and randomly allocate them into the control or treatment group in a 1:1 ratio. The control group will receive acupuncture treatment at 11 local and 4 distal acupuncture points for 20 min twice a week for 6 weeks. The treatment group will receive the same acupuncture treatment as the control group and also take Palmijihwang-hwan for 6 weeks. The primary outcome will be the change in visual analog scale (VAS) score between baseline (visit 1) and completion of the intervention (visit 12), and secondary outcomes will be pain-related clinical relevance (minimal clinical important difference or the proportion of the participants who decrease more than 30, or 50% on VAS), disability (Roland and Morris Disability Questionnaire), quality of life (EuroQol-5D), global assessment (Patient Global Impression of Change), and economic analysis (cost-effectiveness and cost-utility analysis). Additionally, safety will be assessed.

Discussion

The results of our study will provide the clinical evidence about the efficacy, safety, and cost-effectiveness analysis of Palmijihwang-hwan for CLBP. There will be a chance to provide multiple subdivided influence of this treatment with various outcome measures, but lack of placebo is our limitation.

Trial registration

Clinical Research Information Service, KCT0002998. Registered on 12 July 2018.

Catalpol prevents denervated muscular atrophy related to the inhibition of autophagy and reduces BAX/BCL2 ratio via mTOR pathway

Aim

To investigate the effects of catalpol on muscular atrophy induced by sciatic nerve crush injury (SNCI).

Methods

Seventy male Kunming mice were randomized into five groups (n=10): model, sham, catalpol (Cat), rapamycin (Rapa), and catalpol+rapamycin (Rapa+Cat). The ratio of gastrocnemius muscle wet weight (right/left, R/L) between the operated leg (right) and the normal leg (left) was calculated, and acetylcholinesterase (AChE) immunohistochemistry assays were performed to observe the change of motor end plate (MEP), along with the sizes of denervated and innervated muscle fibers. The expression levels of LC3II, TUNEL, BAX/BCL-2, LC3II/LC3I and P62, Beclin1, mTOR, and p-mTOR (ser2448) proteins in muscle were examined by fluorescence immunohistochemistry or Western blotting.

Results

Results show that catalpol improved the results of the grid walking tests by reducing the percentage of foot slips, which increased the gastrocnemius muscle wet weight (R/L), enhanced AChE expression at the MEP, and enlarged the section area of the muscle. The expression of LC3II and TUNEL was significantly inhibited by catalpol. The BAX/BCL-2 ratio was significantly increased in muscles of denervated and control groups. Lower LC3II/LC3I and BAX/BCL-2 ratios in denervated muscles were also detected after catalpol treatment.

Conclusion

These results indicated that apoptosis and autophagy play a role in the regulation of denervation-induced muscle atrophy after SNCI, and catalpol alleviates muscle atrophy through the regulation of muscle apoptosis and autophagy via the mTOR signaling pathway.

Clinical research on the efficacy and safety of Bosinji for low back pain with radiculopathy caused by herniated intervertebral disc of the lumbar spine: A protocol for a multicenter, randomized, controlled equivalence trial

BACKGROUND

A lumbar herniated intervertebral disc (LHIVD) is a common problem that usually causes low back pain and radiating pain. The effectiveness of Bosinji, one of the herbal medicines used for low back pain and radiating pain in patient with LHIVD, has been reported in several studies; however, little clinical evidence is available owing to the methodological limitations in previous studies. Hence, the present study aims to establish the clinical evidence regarding the efficacy and safety of Bosinji in improving pain, function, and quality of life in LHIVD patients.

METHOD/DESIGN

This is a multicenter, open-label, randomized, controlled, and equivalence trial with 2 parallel arms. A total of 74 patients who have low back pain and radiating pain due to LHIVD will be recruited and randomly allocated to the experimental group and control group. The patients in the experimental group and control group will take 2.5 g of Bosinji granule (1.523 g of Bosinji extract) or Loxonin tablet (60 mg of loxoprofen) 3 times a day for 6 weeks. Additionally, both groups will receive the same acupuncture treatment once a week for 6 weeks as a concurrent treatment. Changes in the 100-mm visual analogue scale (VAS) for low back pain after 6 weeks from baseline will be assessed as the primary outcome. Furthermore, the 100-mm VAS for radiating pain, Oswestry disability index (ODI), Roland-Morris disability questionnaire (RMDQ), EuroQol 5 Dimensions 5 Levels (EQ-5D-5L), global perceived effect (GPE), and deficiency syndrome of kidney index (DSKI) will be used to evaluate secondary outcomes. Outcomes will be assessed at baseline and at 3, 6, and 10 weeks after screening. For the safety evaluation, laboratory examinations including complete blood count, liver function test, renal function test, blood coagulation test, inflammation test, and urine analysis will be conducted before and after taking the medications.

DISCUSSION

The results of this trial will be used to establish clinical evidence regarding the use of Bosinji with acupuncture treatment in the treatment of patients with LHIVD.

TRIAL REGISTRATION NUMBER

NCT03386149 (clinicaltrials.gov) and KCT0002848 (Clinical Research Information Service of the Republic of Korea).

Monoterpenes modulating cytokines - A review

Inflammatory response can be driven by cytokine production and is a pivotal target in the management of inflammatory diseases. Monoterpenes have shown that promising profile as agents which reduce the inflammatory process and also modulate the key chemical mediators of inflammation, such as pro and anti-inflammatory cytokines. The main interest focused on monoterpenes were to develop the analgesic and anti-inflammatory drugs. In this review, we summarized current knowledge on monoterpenes that produce anti-inflammatory effects by modulating the release of cytokines, as well as suggesting that which monoterpenoid molecules may be most effective in the treatment of inflammatory disease. Several different inflammatory markers were evaluated as a target of monoterpenes. The proinflammatory and anti-inflammatory cytokines were found TNF-α, IL-1β, IL-2, IL-5, IL-4, IL-6, IL-8, IL-10, IL-12 IL-13, IL-17A, IFNγ, TGF-β1 and IFN-γ. Our review found evidence that NF-κB and MAPK signaling are important pathways for the anti-inflammatory action of monoterpenes. We found 24 monoterpenes that modulate the production of cytokines, which appears to be the major pharmacological mechanism these compounds possess in relation to the attenuation of inflammatory response. Despite the compelling evidence supporting the anti-inflammatory effect of monoterpenes, further studies are necessary to fully explore their potential as anti-inflammatory compounds.

Antiangiogenic effects of catalpol on rat corneal neovascularization

To investigate the effects of catalpol on corneal neovascularization (CNV) and associated inflammation, eye drops (5 mM catalpol or PBS) were administered four times daily to alkali-burn rat models of CNV and inflammation. Clinical evaluations of CNV and the degree of inflammation were performed on days 0, 4, 7, 10 and 14 under slit lamp microscopy. Eyes were collected on day 14 and prepared for hematoxylin and eosin, and immunofluorescence staining; corneal cell apoptosis was investigated via terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) staining. Protein expression levels of angiogenic and proinflammatory factors, including vascular endothelial growth factor (VEGF), pigment epithelium-derived factor (PEDF), tumor necrosis factor-α (TNF-α) and necrosis factor-κB (NF-κB) were determined by western blotting. The effects of catalpol on cell proliferation were investigated in vitro using human umbilical vein endothelial cells (HUVECs) and a Cell Counting kit-8 (CCK-8); alterations in migration and tube formation were investigated via HUVEC wound closure and tube formation assays. HUVEC viability and proliferative ability were inhibited in a dose-dependent manner; catalpol also decreased HUVEC cell migration and tube forming ability. Within alkali-burn rat models, decreased inflammation and CNV was associated with catalpol administration; as demonstrated with TUNEL, corneal cell apoptosis was decreased in response to catalpol. Western blot analysis revealed reduced protein expression levels of VEGF and TNF-α; however, PEDF and phosphorylated-NF-κB p65 were increased due to catalpol administration. The present study demonstrated the inhibitory effects exerted by catalpol on CNV and inflammation within alkali-burned rat models. Topical application of catalpol in vivo was associated with reduced CNV and inflammation; therefore, catalpol may be considered an anti-inflammatory agent for the clinical treatment of CNV.