Serotonin Receptor 2A/C Is Involved in Electroacupuncture Inhibition of Pain in an Osteoarthritis Rat Model

The Role of Web-Based Adaptive Choice-Based Conjoint Analysis Technology in Eliciting Patients' Preferences for Osteoarthritis Treatment

OBJECTIVE

To assess the feasibility of using adaptive choice-based conjoint (ACBC) analysis to elicit patients' preferences for pharmacological treatment of osteoarthritis (OA), patients' satisfaction with completing the ACBC questionnaire, and factors associated with questionnaire completion time.

METHODS

Adult patients aged 18 years and older with a medical diagnosis of OA, experiencing joint pain in the past 12 months, and living in the Northeast of England participated in the study. The participants completed a web-based ACBC questionnaire about their preferences regarding pharmaceutical treatment for OA using a touchscreen laptop independently, and accordingly, the questionnaire completion time was measured. Moreover, the participants completed a pen-and-paper feedback form about their experience in completing the ACBC questionnaire.

RESULTS

Twenty participants aged 40 years and older, 65% females, 75% had knee OA, and suffering from OA for more than 5 years participated in the study. About 60% of participants reported completing a computerized questionnaire in the past. About 85% of participants believed that the ACBC task helped them in making decisions regarding their OA medications, and 95% agreed or strongly agreed that they would be happy to complete a similar ACBC questionnaire in the future. The average questionnaire completion time was 16 min (range 10-24 min). The main factors associated with longer questionnaire completion time were older age, never using a computer in the past, and no previous experience in completing a questionnaire.

CONCLUSIONS

The ACBC analysis is a feasible and efficient method to elicit patients' preferences for pharmacological treatment of OA, which could be used in clinical settings to facilitate shared decision-making and patient-centered care. The ACBC questionnaire completion consumes a significantly longer time for elderly participants, who never used a computer, and never completed any questionnaire previously. Therefore, the contribution of patients and public involvement (PPI) group in the development of the ACBC questionnaire could facilitate participants' understanding and satisfaction with the task. Future research including patients with different chronic conditions may provide more useful information about the efficiency of ACBC analysis in eliciting patients' preferences for osteoarthritis treatment.

Effects of Acupuncture, Moxibustion, Cupping, and Massage on Sports Injuries: A Narrative Review

With the evolution of society, an increasing number of people have realized the importance of sports on human health. However, participation in sports is a double-edged sword as improperly exercising can lead to injury. Many athletes and patients with sports injuries choose traditional Chinese medicine (TCM) when modern medicine fails to relieve their musculoskeletal symptoms. TCM is a splendid legacy of Chinese civilization whose therapies are effective, economical, and convenient, with some administration by trained patients at home. This review analyzes the literature on the application of acupuncture, moxibustion, massage, and cupping in sports injuries to provide novel ideas for the application of TCM in sports medicine.

Effective Oriental Magic for Analgesia: Acupuncture

Pain is a kind of complex physiological and psychological symptom, which makes the person debilitated and uncomfortable. Some persistent pain is unbearable for the patients, reducing the quality of life and bringing considerable pressure to the individuals and society. Pain killers seem to be effective in analgesia for patients, but their safety and addiction are crucial issues. From the theory of traditional Chinese medicine (TCM), the blocked meridian is the main cause of pain, and effective acupuncture can play a positive analgesic effect. Acupuncture that can date back thousands of years is one of the ancient medical practices in China. Its safety and effectiveness are respected. Based on its superior safety and inferior side effects, it has been gradually recognized as a therapeutic intervention method for complementary medicine, which is also generally used to treat multiple pain diseases. It is shown by modern medical studies that neurotransmitters are the material basis for the acupuncture effect, and the effect of acupuncture analgesia is related to changes in neurotransmitters. However, the specific mechanism has not been elucidated. This review aims to comprehensively discuss the historical evolution of acupuncture analgesia, clinical research of acupuncture analgesia, comparison of acupuncture and drug therapy, the neurotransmitter mechanism of acupuncture analgesia, the effect of acupuncture manipulation on analgesia, and bibliometric analysis of acupuncture treatment for pain, to explore the superiority and related mechanism of acupuncture analgesia from different aspects, and to provide a more effective treatment for alleviating patients' pain.

Spinal 5-HT2A Receptor is Involved in Electroacupuncture Inhibition of Chronic Pain

Knee osteoarthritis (KOA) is a highly prevalent, chronic joint disorder, and it is a typical disease which can develop chronic pain. Our previous study has proved that endocannabinoid (2-AG)-CB1R-GABA-5-HT pathway is involved in electroacupuncture (EA) mediated inhibition of chronic pain. However, it is still unclear which among the 5-HT receptor subtype is involved in EA evoked 5-HT mediated inhibition of chronic pain in the dorsal spinal cord. 5-HT_2A is a G protein-coupled receptor and it is involved in 5-HT descending pain modulation system. We found that EA treatment at frequency of 2 Hz +1 mA significantly increased the expression of 5-HT_2A receptor in the dorsal spinal cord and intrathecal injection of 5-HT_2A receptor antagonist or agonist reversed or mimicked the analgesic effect of EA in each case respectively. Intrathecal injection of a selective GABA_A receptor antagonist Bicuculline also reversed the EA effect on pain hypersensitivity. Additionally, EA treatment reversed the reduced expression of GABA_A receptor and KCC2 in the dorsal spinal cord of KOA mice. Furthermore, we demonstrated that intrathecal 5-HT_2A receptor antagonist/agonist reversed or mimicked the effect of EA up-regulate of KCC2 expression, respectively. Similarly, intrathecal injection of PLC and PKC inhibitors prevented both anti-allodynic effect and up-regulation of KCC2 expression by EA treatment. Our data suggest that EA treatment up-regulated KCC2 expression through activating 5-HT_2A-Gq-PLC-PKC pathway and enhanced the inhibitory function of GABA_A receptor, thereby inhibiting chronic pain in a mouse model of KOA.

The Therapeutic Effects of Acupuncture and Electroacupuncture on Cancer-related Symptoms and Side-Effects

In addition to cancer-related death, malignant progression also leads to a series of symptoms and side-effects, which would detrimentally affect cancer patients' the quality of life, adversely influence their adherence to treatments, and, therefore, negatively affect their long-term survival. Acupuncture and electroacupuncture (EA), as two classic treatment methods in traditional Chinese medicine, have been widely employed to cure various diseases. Recently, the clinical application of acupuncture and EA in cancer patients has received great attention. In this review, we summarized the clinical application of acupuncture and EA in alleviating the cancer symptoms, reducing the cancer treatment-related side-effects, and relieving the cancer pain. The symptoms and side-effects discussed in this review include fatigue, insomnia, chemotherapy-associated dyspepsia syndrome (CADS), pain, xerostomia, and anxiety and depression. The underlying mechanisms of the therapeutic effects of acupuncture and EA might be related to the regulation of the mitochondrial function, coordination of the activity of the nervous system, adjustment of the production of neurotransmitters, and alleviation of the immune responses. In conclusion, acupuncture and EA have been proved to be beneficial for cancer patients. More research, however, is required to clarify the potential mechanisms behind acupuncture and EA for widespread adoption in clinical application.

5-HT7 Receptor Is Involved in Electroacupuncture Inhibition of Chronic Pain in the Spinal Cord

Knee osteoarthritis (KOA) is a common and disabling condition characterized by attacks of pain around the joints, and it is a typical disease that develops chronic pain. Previous studies have proved that 5-HT₁, 5-HT₂, and 5-HT₃ receptors in the spinal cord are involved in electroacupuncture (EA) analgesia. The 5-HT₇ receptor plays antinociceptive role in the spinal cord. However, it is unclear whether the 5-HT₇ receptor is involved in EA analgesia. The 5-HT₇ receptor is a stimulatory G-protein (Gs)-coupled receptor that activates adenylyl cyclase (AC) to stimulate cyclic adenosine monophosphate (cAMP) formation, which in turn activates protein kinase A (PKA). In the present study, we found that EA significantly increased the tactile threshold and the expression of the 5-HT₇ receptor in the dorsal spinal cord. Intrathecal injection of 5-HT₇ receptor agonist AS-19 mimicked the analgesic effect of EA, while a selective 5-HT₇ receptor antagonist reversed this effect. Moreover, intrathecal injection of AC and PKA antagonists prior to EA intervention prevented its anti-allodynic effect. In addition, GABA_A receptor antagonist bicuculline administered (intrathecal, i.t.) prior to EA intervention blocked the EA effect on pain hypersensitivity. Our data suggest that the spinal 5-HT₇ receptor activates GABAergic neurons through the Gs–cAMP–PKA pathway and participates in EA-mediated inhibition of chronic pain in a mouse model of KOA.

Involvement of 5-HT2A, 5-HT2B and 5-HT2C receptors in mediating the ventrolateral orbital cortex-induced antiallodynia in a rat model of neuropathic pain

The present study examined the roles of 5-HT2A, 5-HT2B and 5-HT2C receptor subtypes in mediating the ventrolateral orbital cortex (VLO)-induced antiallodynia in a rat model of neuropathic pain induced by spared nerve injury (SNI). Change of mechanical paw withdrawal threshold (PWT) was measured using von-Frey filaments. Microinjection of preferential or selective 5-HT2A/C, 5-HT2B and 5-HT2C receptor agonists, (±)-1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), α-methyl-5-(2-thienylmethoxy)-1H-Indole-3-ethanamine hydrochloride (BW723C86) and 1-(3-Chlorophenyl)-piperazine hydrochloride (m-CPP) into the VLO significantly depressed allodynia induced by SNI, and the inhibitory effect of DOI was blocked or attenuated by selective 5-HT2A/C receptor antagonists ketanserin (+)-tartrate salt (ketanserin) and 5-HT2A receptor antagonist R-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidinemethanol (M100907); the effects of BW723C86 and m-CPP were antagonized by 5-HT2B receptor antagonists N-(1-Methyl-1H-5-indolyl)-N'-(3-methyl-5-isothiazolyl)urea (SB204741) and 5-HT2C receptor antagonist RS102221 hydrochloride hydrate (RS-102221), respectively. These results suggest that 5-HT2A, 5-HT2B, 5-HT2C receptor subtypes are involved in mediating the VLO-induced antiallodynia in the neuropathic pain state.

The Role of Neuroglial Crosstalk and Synaptic Plasticity-Mediated Central Sensitization in Acupuncture Analgesia

Although pain is regarded as a global public health priority, analgesic therapy remains a significant challenge. Pain is a hypersensitivity state caused by peripheral and central sensitization, with the latter considered the culprit for chronic pain. This study summarizes the pathogenesis of central sensitization from the perspective of neuroglial crosstalk and synaptic plasticity and underlines the related analgesic mechanisms of acupuncture. Central sensitization is modulated by the neurotransmitters and neuropeptides involved in the ascending excitatory pathway and the descending pain modulatory system. Acupuncture analgesia is associated with downregulating glutamate in the ascending excitatory pathway and upregulating opioids, 𝛾-aminobutyric acid, norepinephrine, and 5-hydroxytryptamine in the descending pain modulatory system. Furthermore, it is increasingly appreciated that neurotransmitters, cytokines, and chemokines are implicated in neuroglial crosstalk and associated plasticity, thus contributing to central sensitization. Acupuncture produces its analgesic action by inhibiting cytokines, such as interleukin-1β, interleukin-6, and tumor necrosis factor-α, and upregulating interleukin-10, as well as modulating chemokines and their receptors such as CX3CL1/CX3CR1, CXCL12/CXCR4, CCL2/CCR2, and CXCL1/CXCR2. These factors are regulated by acupuncture through the activation of multiple signaling pathways, including mitogen-activated protein kinase signaling (e.g., the p38, extracellular signal-regulated kinases, and c-Jun-N-terminal kinase pathways), which contribute to the activation of nociceptive neurons. However, the responses of chemokines to acupuncture vary among the types of pain models, acupuncture methods, and stimulation parameters. Thus, the exact mechanisms require future clarification. Taken together, inhibition of central sensitization modulated by neuroglial plasticity is central in acupuncture analgesia, providing a novel insight for the clinical application of acupuncture analgesia.

A topical ointment formulation containing leaves' powder of Lawsonia inermis accelerate excision wound healing in Wistar rats

AIM

Lawsonia inermis (LI), a naturally grown or cultivated shrub in Northeast of Africa and India, has been traditionally used as a strong remedy for several injuries. However, few studies have reported its use as a cicatrizing agent. The aim of this study was to evaluate the effect of daily application of an ointment prepared with LI leaves' powder on wound healing in Wistar rats.

MATERIALS AND METHODS

Twenty female Wistar rats were used in this study. Excisional wound model was realized by removing skin from the dorsal part of the neck of each animal. Wounds have been then treated by a daily application of LI ointment prepared by mixing leaves' powder to petroleum jelly in test group and by simple application of petroleum jelly in control group. Evaluation of wound healing activity was then based on calculating the percentage of wound contraction, period of epithelialization, and wound index every 3 days for a period of 24 days, then, a histological study of the healed excised wound was performed.

RESULTS

Treatment with LI has shown excellent wound healing activity, since it has increased percent of wound contraction, and reduced period of epithelialization and wound index as compared to control (p<0.05). These results have been supported by the histological findings that revealed better epithelialization, dermal differentiation, collagen fiber orientation, and angiogenesis in LI treated rats compared to control (p<0.05).

CONCLUSION

We can conclude that LI leaves' can be used as a potential wound healing agent.

Acupuncture for Pain Management: Molecular Mechanisms of Action

Acupuncture reduces pain by activating specific areas called acupoints on the patient’s body. When these acupoints are fully activated, sensations of soreness, numbness, fullness, or heaviness called De qi or Te qi are felt by clinicians and patients. There are two kinds of acupuncture, manual acupuncture and electroacupuncture (EA). Compared with non-acupoints, acupoints are easily activated on the basis of their special composition of blood vessels, mast cells, and nerve fibers that mediate the acupuncture signals. In the spinal cord, EA can inhibit glial cell activation by down-regulating the chemokine CX3CL1 and increasing the anti-inflammatory cytokine interleukin-10. This inhibits P38 mitogen-activated protein kinase and extracellular signal-regulated kinase pathways, which are associated with microglial activation of the C-Jun N-terminal kinase signaling pathway and subsequent astrocyte activation. The inactivation of spinal microglia and astrocytes mediates the immediate and long-term analgesic effects of EA, respectively. A variety of pain-related substances released by glial cells such as the proinflammatory cytokines tumor necrosis factor [Formula: see text], interleukin-1[Formula: see text], interleukin-6, and prostaglandins such as prostaglandins E2 can also be reduced. The descending pain modulation system in the brain, including the anterior cingulated cortex, the periaqueductal gray, and the rostral ventromedial medulla, plays an important role in EA analgesia. Multiple transmitters and modulators, including endogenous opioids, cholecystokinin octapeptide, 5-hydroxytryptamine, glutamate, noradrenalin, dopamine, [Formula: see text]-aminobutyric acid, acetylcholine, and orexin A, are involved in acupuncture analgesia. Finally, the “Acupuncture [Formula: see text]” strategy is introduced to help clinicians achieve better analgesic effects, and a newly reported acupuncture method called acupoint catgut embedding, which injects sutures made of absorbable materials at acupoints to achieve long-term effects, is discussed.

Effects of intensity of electroacupuncture on chronic pain in patients with knee osteoarthritis: a randomized controlled trial

BACKGROUND

Conditioned pain modulation (CPM) is impaired in people with chronic pain such as knee osteoarthritis (KOA). The purpose of this randomized, controlled clinical trial was to investigate whether strong electroacupuncture (EA) was more effective on chronic pain by strengthening the CPM function than weak EA or sham EA in patients with KOA.

METHODS

In this multicenter, three-arm parallel, single-blind randomized controlled trial, 301 patients with KOA were randomly assigned. Patients were randomized into three groups based on EA current intensity: strong EA (> 2 mA), weak EA (< 0.5 mA), and sham EA (non-acupoint). Treatments consisted of five sessions per week, for 2 weeks. Primary outcome measures were visual analog scale (VAS), CPM function, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

RESULTS

Three hundred one patients with KOA were randomly assigned, among which 271 (90.0%) completed the study (mean age 63.93 years old). One week of EA had a clinically important improvement in VAS and WOMAC but not in CPM function. After 2 weeks treatment, EA improved VAS, CPM, and WOMAC compared with baseline. Compared with sham EA, weak EA (3.8; 95% CI 3.45, 4.15; P < .01) and strong EA (13.54; 95% CI 13.23, 13.85; P < .01) were better in improving CPM function. Compared with weak EA, strong EA was better in enhancing CPM function (9.73; 95% CI 9.44, 10.02; P < .01), as well as in reducing VAS and total WOMAC score.

CONCLUSION

EA should be administered for at least 2 weeks to exert a clinically important effect on improving CPM function of KOA patients. Strong EA is better than weak or sham EA in alleviating pain intensity and inhibiting chronic pain.

TRIAL REGISTRATION

This study was registered with the Chinese Clinical Trial Registry ( ChiCTR-ICR-14005411 ), registered on 31 October 2014.

Electroacupuncture potentiates peripheral CB2 receptor-inhibited chronic pain in a mouse model of knee osteoarthritis

Purpose

Knee osteoarthritis (KOA) is a highly prevalent, chronic joint disorder, with chronic pain as its typical symptom. Although studies have shown that an activated peripheral CB2 receptor can reduce acute pain, whether the CB2 receptor is involved in electroacupuncture (EA) inhibiting chronic pain and the involved mechanism remains unclear. The aim of this study was to investigate whether EA may strengthen peripheral CB2 receptor-inhibited chronic pain in a mouse model of KOA.

Materials and methods:

KOA was induced by intra-articular injection of monosodium iodoacetate (MIA) into the left knee joint of mice. Thermal hyperalgesia was tested with the hot plate test, and mechanical allodynia was quantified using von Frey filaments. The expression of CB2 receptor and IL-1β were quantified by using immunofluorescence labeling.

Results

EA treatment at 2 Hz+1 mA significantly increased the expression of CB2 receptor in fibroblasts and decreased the expression of IL-1β in the menisci compared with that in the KOA group. However, EA had no effect on the expression of IL-1β in CB2^−/− mice. At 2 Hz+1 mA, EA significantly increased mechanical threshold, thermal latency, and weight borne after KOA modeling. However, knockout of the CB2 receptor blocked these effects of EA. After 2 Hz+1 mA treatment, EA significantly reduced the Osteoarthritis Research Society International (OARSI) score after KOA modeling. However, EA had no significant effect on the OARSI score in CB2^−/− mice.

Conclusion

EA reduced the expression of IL-1β by activating the CB2 receptor, thus inhibiting the chronic pain in the mouse model of KOA.

Tackling Osteoarthritic Knee Pain with Electroacupuncture

Electroacupuncture (EA) has been widely used in pain relief. Clinical evidence has revealed its unique advantages and effectiveness in alleviating pain. Studies on EA and pain relief have revealed that EA displays greater analgesic effects for different types of pain in comparison to manual acupuncture. Here, we reviewed the clinical application and mechanism of EA in treating osteoarthritic knee pain and its influence factors in curative effect.

Electroacupuncture alleviates chemotherapy-induced pain through inhibiting phosphorylation of spinal CaMKII in rats

BACKGROUND

Current medical treatments for chemotherapy-induced pain (CIP) are either ineffective or have adverse side effects. Acupuncture may alleviate CIP, but its effectiveness against this condition has not been studied. Paclitaxel causes neuropathic pain in cancer patients.

METHODS

We evaluated the effects of electroacupuncture (EA) on paclitaxel-induced CIP in a rat model. Paclitaxel (2 mg/kg) or vehicle was injected (i.p.) on alternate days of 0-6. The resulting pain was treated with 10 Hz/2 mA/0.4 ms pulse EA for 30 min at the equivalent of human acupoint GB30 (Huantiao) once every other day between days 14 and 26. For sham control, EA needles were inserted into GB30 without stimulation. Von Frey filaments with bending forces of 2-8 g and 15 g were used to assess mechanical allodynia and hyperalgesia, respectively, on day 13 and once every other day between 14-26 days and then for 2-3 weeks after EA treatment.

RESULTS

Compared to sham control, EA significantly alleviated paclitaxel-induced mechanical allodynia and hyperalgesia, as shown by less frequent withdrawal responses to the filaments. The alleviation of allodynia/hyperalgesia lasted up to 3 weeks after the EA treatment. EA significantly inhibited phosphorylation of Ca2+ /calmodulin-dependent protein kinase II (CaMKII) in the spinal cord. KN-93, a selective inhibitor of p-CaMKII, inhibited mechanical allodynia/hyperalgesia and p-CaMKII. 5-HT1A receptor antagonist blocked EA inhibition of allodynia/hyperalgesia and p-CaMKII.

CONCLUSIONS

Electroacupuncture activates 5-HT 1A receptors in the spinal cord and inhibits p-CaMKII to alleviate both allodynia and hyperalgesia. The data support acupuncture/EA as a complementary therapy for CIP.

SIGNIFICANCE

Electroacupuncture (EA) activates spinal 5-HT1A receptors to inhibit p-CaMKII to alleviate paclitaxel-induced pain. Acupuncture/EA may be used as a complementary therapy for CIP.

A rat model of knee osteoarthritis suitable for electroacupuncture study

Acupuncture is widely used for knee osteoarthritis (KOA) treatment in clinical practice. In the present study, we aimed to set a standard KOA animal model for electroacupuncture (EA) study and provide an acupuncture recipe for further KOA studies. Rats intra-articularly administered monosodium iodoacetate (MIA, 0.3, 1 or 3 mg respectively, n=12 each) were evaluated for pain-like behavior: paw withdrawal mechanical threshold, weight bearing deficit, and joint pathological changes (OARSI score) until 28 days after injury. Then by using the suitable dose (1 mg MIA), therapeutic effects of EA treatment (bilateral ST36 and ST35 acupoints, 2/10 Hz, 30 min/d, 6d/w, 2w) were evaluated in 3 groups (n=16 each): Early-on EA, Mid-term EA and Delayed EA, in which EA was started on day 1, day 7 or day 14 after MIA injection. Both 1 mg and 3 mg MIA induced significant joint damage and persistent pain behavior. But animals accepted 3 mg MIA rapidly developed cartilage and bone damage within 14 days. Early-on EA treatment provided significant pain relief and joint structure preservation in KOA rats. Mid-term EA treatment only reduced pain, while delayed EA treatment resulted in no effects in both aspects. 1 mg of MIA produces steady pain behavior and progressive joint damage, which was suitable for EA treatment evaluation. Early-on EA treatment provided both joint protection and pain reduction, while Mid-term EA could only be used for studying EA-induced analgesia in KOA.

Transient Receptor Potential Channel and Interleukin-17A Involvement in LTTL Gel Inhibition of Bone Cancer Pain in a Rat Model

Cancer pain management is a challenge for which Chinese herbal medicine might be useful. To study the spinal mechanisms of the Chinese medicated gel Long-Teng-Tong-Luo (LTTL), a 7-herb compound, on bone cancer pain, a bone cancer pain model was made by inoculating the tibias of female rats with Walker 256 cells. LTTL gel or inert gel, 0.5 g/cm(2)/d, was applied to the skin of tumor-bearing tibias for 21 days beginning a day after the inoculation. Mechanical threshold and paw withdrawal latency to thermal stimulation was measured. Transient receptor potential (TRP) cation channels in lumbar dorsal root ganglia (DRG) were immunostained and counted, and lumbar spinal cord interleukin-17A (IL-17A) was measured with real-time polymerase chain reaction and enzyme-linked immunosorbent assay. TRP antagonists and interleukin (IL)-17A antibodies were intrathecally administered to determine their effects on bone cancer pain. The gel significantly (P < .05) alleviated cancer-induced mechanical allodynia and thermal hyperalgesia and inhibited cancer-enhanced expression of IL-17A in spinal astrocytes and the TRP subfamily members V1, A1, and V4 in lumbar DRG. Intrathecal TRP antagonists at 10 µg significantly (P < .05) attenuated mechanical allodynia, thermal hyperalgesia, and IL-17A expression, indicating that TRP channels facilitate spinal IL-17 expression and cancer pain. IL-17A antibodies inhibited cancer pain, suggesting that IL-17A promotes such pain. The data show that LTTL gel inhibits cancer pain, and this might be accounted for by the decrease in expression of DRG TRP channels and spinal astrocyte IL-17A.

Wound Healing Activity of a Traditionally Used Poly Herbal Product in a Burn Wound Model in Rats

BACKGROUND

Burns are known as one of the most common and destructive forms of injury with a vast spectrum of consequences. Despite the discovery of various antibacterial and antiseptic agents, burn wound healing still has remained a challenge to modern medicine. Plants, with a valuable traditional support, have been considered as potential agents for prevention and treatment of disorders in recent years. However, modern scientific methods should be applied to validate the claims about the therapeutic effects of the herbal products.

OBJECTIVES

This study was conducted to evaluate the wound-healing activity of a poly herbal cream (PHC), retrieved from Iranian Traditional Medicine (ITM), in a rat burn wound model in Iran.

MATERIALS AND METHODS

In this experimental study, PHC containing aqueous extracts of Malva sylvestris and Solanum nigrum leaves and oily extract of Rosa damascena petals was used. Second-degree burn wounds were induced in four groups of five rats each. Group 1 received no treatment while groups 2, 3 and 4 were given cream base, silver sulfadiazine (SS) 1% and PHC, respectively to compare the efficacy of PHC with the negative and positive control groups. The percentage of wound healing on days 2, 6, 10 and 14 and histopathological parameters of healed wounds on the 14th day were assessed. Antioxidant and antimicrobial activities of PHC were evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and micro-dilution methods, respectively.

RESULTS

There was a significant improvement in healing percentage of PHC-treated rats in comparison to the other groups at the end of the treatment period (87.0% ± 2.1% for PHC in comparison to 32.2% ± 1.6%, 57.0% ± 5.3% and 70.8% ± 3.5% for the control, cream base and SS groups, respectively). Moreover, the healed wounds in PHC-treated animals contained less inflammatory cells and had desirable re-epithelialization with remarkable neovascularization. In addition to the antioxidant activity, PHC exhibited antibacterial effect against Staphylococcus aureus.

CONCLUSIONS

Poly herbal cream experimentally and histopathologically revealed a burn wound healing activity probably due to the antioxidant, anti-inflammatory and antimicrobial activities of its phytochemical contents. Therefore, this study confirms the use of M. sylvestris, S. nigrum and R. damascena in burn prescriptions in ITM.

Immediate effects of electroacupuncture and manual acupuncture on pain, mobility and muscle strength in patients with knee osteoarthritis: a randomised controlled trial

OBJECTIVE

To compare the immediate effects of electroacupuncture and manual acupuncture on pain, mobility and muscle strength in patients with knee osteoarthritis.

METHODS

Sixty patients with knee osteoarthritis, with a pain intensity of ≥2 on the pain Numerical Rating Scale, were included. The patients were randomised into two groups: manual acupuncture and electroacupuncture. Pain intensity, degree of dysfunction (Timed Up and Go (TUG) test), maximal voluntary isometric contraction and pressure pain threshold were assessed before and after a single session of manual acupuncture or electroacupuncture treatments.

RESULTS

Both groups showed a significant reduction in pain intensity (p<0.001) and time to run the TUG test after the acupuncture treatment (p=0.005 for the manual acupuncture group and p=0.002 for the electroacupuncture group). There were no differences between the groups regarding pain intensity (p=0.25), TUG test (p=0.70), maximum voluntary isometric contraction (p=0.43) or pressure pain threshold (p=0.27).

CONCLUSIONS

This study found no difference between the immediate effects of a single session of manual acupuncture and electroacupuncture on pain, muscle strength and mobility in patients with knee osteoarthritis.

TRIAL REGISTRATION NUMBER

RBR-9TCN2X.

Mechanisms of acupuncture-electroacupuncture on persistent pain

In the last decade, preclinical investigations of electroacupuncture mechanisms on persistent tissue injury (inflammatory), nerve injury (neuropathic), cancer, and visceral pain have increased. These studies show that electroacupuncture activates the nervous system differently in health than in pain conditions, alleviates both sensory and affective inflammatory pain, and inhibits inflammatory and neuropathic pain more effectively at 2 to 10 Hz than at 100 Hz. Electroacupuncture blocks pain by activating a variety of bioactive chemicals through peripheral, spinal, and supraspinal mechanisms. These include opioids, which desensitize peripheral nociceptors and reduce proinflammatory cytokines peripherally and in the spinal cord, and serotonin and norepinephrine, which decrease spinal N-methyl-D-aspartate receptor subunit GluN1 phosphorylation. Additional studies suggest that electroacupuncture, when combined with low dosages of conventional analgesics, provides effective pain management which can forestall the side effects of often-debilitating pharmaceuticals.

Osteoarthritis pain mechanisms: basic studies in animal models

OBJECTIVE

Osteoarthritis (OA) is a complex and painful disease of the whole joint. At present there are no satisfying agents for treating OA. To promote OA research and improved treatment, this review summarizes current preclinical evidence on the development of OA.

METHODS

Preclinical OA research was searched and key findings are summarized and commented.

RESULTS

Mechanisms of OA-associated pain have been studied in rodent knee OA models produced by intra-knee injection of the chondrocyte glycolytic inhibitor mono-iodoacetate (MIA), surgery, or spontaneous development in some species. These models are clinically relevant in terms of histological damage and functional changes, and are used to study mechanisms underlying mechanical, thermal, ambulatory, body weight supporting-evoked, and ongoing OA pain. Recent peripheral, spinal, and supraspinal biochemical and electrophysiological studies in these models suggest that peripheral pro-inflammatory mediators and neuropeptides sensitize knee nociceptors. Spinal cytokines and neuropeptides promote OA pain, and peripheral and spinal cannabinoids inhibit OA pain respectively through cannabinoid-1 (CB1) and CB1/CB2 receptors. TRPV1 and metalloproteinases contribute and supraspinal descending facilitation of 5-hydroxytryptamine (5-HT)/5-HT 3 receptors may also contribute to OA pain. Conditioned place preference tests demonstrate that OA pain induces aversive behaviors, suggesting the involvement of brain. During OA, brain functional connectivity is enhanced, but at present it is unclear how this change is related to OA pain.

CONCLUSION

Animal studies demonstrate that peripheral and central sensitization contributes to OA pain, involving inflammatory cytokines, neuropeptides, and a variety of chemical mediators. Interestingly, brainstem descending facilitation of 5-HT/5-HT3 receptors plays a role OA pain.

DAMGO in the central amygdala alleviates the affective dimension of pain in a rat model of inflammatory hyperalgesia

Pain has sensory-discriminative and emotional-affective dimensions. Recent studies show that the affective component can be assessed with a conditioned place avoidance (CPA) test. We hypothesized that systemic morphine before a post-conditioning test would more potently attenuate the affective aspect compared to the sensory component and that [d-Ala2-N-Me-Phe4, Gly-ol5]-enkephalin (DAMGO), a μ-selective opioid receptor agonist, injected into the central nucleus of the amygdala (CeA) would reduce established CPA. A rat model of inflammatory pain, produced by a complete Freund adjuvant (CFA) injection into the hind paw, was combined with a CPA test. Three experiments were performed on adult male Sprague-Dawley rats. Systemic morphine (0.5 or 1.0mg/kg) in Experiment 1, intrathecal (i.t.) morphine (2.5 μg/rat) in Experiment 2, and intra-CeA DAMGO (7.7-15.4 ng/0.4 μl) in Experiment 3 were given to CFA-injected rats (n=6-8/group) prior to a post-conditioning test. Saline-injected rats were used as control. Time spent in a pain-paired compartment was recorded twice, before conditioning and after a post-conditioning test. Paw withdrawal latency (PWL) to a noxious thermal stimulus was measured before experiment at day-1 and after the post-conditioning test; hyperalgesia was defined as a decrease in PWL. The data showed that CFA-injected rats had significantly negative CPA compared to those of saline-injected rats (P<0.05). Low-dosage systemic morphine significantly (P<0.05) reduced CFA-induced CPA but had no effect on PWL. I.t. morphine did not inhibit the display of CPA but significantly increased PWL, suppressing hyperalgesia (P<0.05). Intra-CeA DAMGO significantly inhibited the display of CPA compared to saline (P<0.05) but had no effect on PWL. The data demonstrate that morphine attenuates the affective component more powerfully than it does the sensory and suggests that the sensory and the emotional-affective dimensions are underpinned by different mechanisms.

Modulation of brain electroencephalography oscillations by electroacupuncture in a rat model of postincisional pain

The present study aimed to investigate how ongoing brain rhythmical oscillations changed during the postoperative pain and whether electroacupuncture (EA) regulated these brain oscillations when it relieved pain. We established a postincisional pain model of rats with plantar incision to mimic the clinical pathological pain state, tested the analgesic effects of EA, and recorded electroencephalography (EEG) activities before and after the EA application. By analysis of power spectrum and bicoherence of EEG, we found that in rats with postincisional pain, ongoing activities at the delta-frequency band decreased, while activities at theta-, alpha-, and beta-frequency bands increased. EA treatment on these postincisional pain rats decreased the power at high-frequency bands especially at the beta-frequency band and reversed the enhancement of the cross-frequency coupling strength between the beta band and low-frequency bands. After searching for the PubMed, our study is the first time to describe that brain oscillations are correlated with the processing of spontaneous pain information in postincisional pain model of rats, and EA could regulate these brain rhythmical frequency oscillations, including the power and cross-frequency couplings.

Electroacupuncture alleviates affective pain in an inflammatory pain rat model

Pain has both sensory-discriminative and emotional-affective dimensions. Previous studies demonstrate that electroacupuncture (EA) alleviates the sensory dimension but do not address the affective. An inflammatory pain rat model, produced by a complete Freund adjuvant (CFA) injection into the hind paw, was combined with a conditioned place avoidance (CPA) test to determine whether EA inhibits spontaneous pain-induced affective response and, if so, to study the possibility that rostral anterior cingulate cortex (rACC) opioids underlie this effect. Male Sprague-Dawley rats (250-275 g, Harlan) were used. The rats showed place aversion (i.e. affective pain) by spending less time in a pain-paired compartment after conditioning than during a preconditioning test. Systemic non-analgesic morphine (0.5 and 1.0 mg/kg, i.p.) inhibited the affective reaction, suggesting that the affective dimension is underpinned by mechanisms different from those of the sensory dimension of pain. Morphine at 0.5 and at 1 mg/kg did not induce reward. Rats given EA treatment before pain-paired conditioning at GB 30 showed no aversion to the pain-paired compartment, indicating that EA inhibited the affective dimension. EA treatment did not produce reward or aversive effect. Intra-rACC administration of D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr amide (CTOP), a selective mu opioid receptor antagonist, but not norbinaltorphimine (nor-BNI), a selective kappa opioid receptor antagonist, blocked EA inhibition of the affective dimension. These data demonstrate that EA activates opioid receptors in the rACC to inhibit pain-induced affective responses and that EA may be an effective therapy for both the sensory-discriminative and the affective dimensions of pain.

Spinal interleukin-17 promotes thermal hyperalgesia and NMDA NR1 phosphorylation in an inflammatory pain rat model

It is known that interleukin-17 (IL-17) is associated with autoimmune disorders and that peripheral IL-17 plays a role in arthritis and neuropathic pain. The present study investigated the possibility of spinal cell expression of IL-17 during inflammatory pain and possible IL-17 involvement in such pain. Hyperalgesia was induced by injecting complete Freund adjuvant (CFA, 0.08mL, 40μg Mycobacterium tuberculosis) into one hind paw of the rat. Paw withdrawal latency (PWL) was tested before (-48h) and 2 and 24h after CFA injection to assess hyperalgesia. IL-17 antibody (0.2-2μg/rat) was given intrathecally (i.t.) 24h before CFA to block the action of basal IL-17 and 2h before each of 2 PWL tests to block CFA-induced IL-17. I.t. recombinant IL-17 (10-400ng per rat) was administered to naive rats to determine its effects on PWL and phosphorylated NR1 (p-NR1). p-NR1 modulates N-methyl-d-aspartate receptor (NMDAR) activity to facilitate pain. Spinal cords were removed for IL-17 immunostaining, double immunostaining of IL-17/cell markers and IL-17 receptor A (IL-17RA)/NR1, for Western blot testing of IL-17, p-NR1, IL-17RA, and GFAP, for in situ IL-17RA hybridization, and for real time polymerase chain reaction of IL-17RA. The data reveal that IL-17 is up-regulated in activated and nonactivated astrocytes; that IL-17RA is localized in NR1-immunoreactive neurons and up-regulated; and that IL-17 antibody at 2μg/rat significantly increased PWL (P<.05) and decreased p-NR1 and IL-17RA compared to control in CFA- and IL-17-injected rats. The results suggest that spinal IL-17 is produced by astrocytes and enhances p-NR1 to facilitate pain.

Recent Non-Interventional Advances in Cancer Pain Among Singapore Patients

Introduction: Pain is a common symptom in cancer patients, but very little information about the prevalence, severity, and treatment of pain in cancer patients in Singapore is available. Therefore, our prospective survey in the National Cancer Centre (NCC) outpatients is incorporated in this report. In addition, a review concerning the recent advances on non-interventional pain management in cancer treatment, which is relevant in the context, is discussed. Materials and Methods: For the prospective survey, a questionnaire was distributed for self-administration by patients while waiting for consultation at the NCC outpatient departments. Literature searches on advances in pain management were conducted, reviewed and discussed. Results: In the last decade, there have been advances in pain pharmacology ranging from wider therapeutic options and management approaches to novel delivery techniques. Acupuncture and massage therapy became increasingly popular among cancer patients. Some clinical trials of acupuncture show benefits in palliation of cancer pain. From the prospective survey, 41.2% of the responders reported pain in the past week, and only 70.8% talked to their doctors about their pain. One third of the patients received analgesics. Of these, 86.5% said that they were taking the prescribed medications, however, 37.4% admitted to having difficulties taking them. Non-drug methods were used by 25.4% of the patients. Medicated oil, cream or gel was used by 49.3%; only 2.6% reported use of Chinese herbs. Conclusion: Pain is a significant symptom in outpatients attending a cancer centre, affecting 41.2% of the patients. Although majority of patients who suffered from pain reported this to doctors, much more medical effort is needed to help patients to relieve their pain and proper complementary therapy could be considered. Key words: Cancer outpatients, Complementary therapies, Non-pharmacological pain treatments, Pain prevalence

The effects of opioid receptor antagonists on electroacupuncture-produced anti-allodynia/hyperalgesia in rats with paclitaxel-evoked peripheral neuropathy

Research supports the effectiveness of acupuncture for conditions such as chronic low back and knee pain. In a five-patient pilot study the modality also improved the symptoms of chemotherapy-induced neuropathic pain. Using an established rat model of paclitaxel-induced peripheral neuropathy, we evaluated the effect of electroacupuncture (EA) on paclitaxel-induced hyperalgesia and allodynia that has not been studied in an animal model. We hypothesize that EA would relieve the paclitaxel-induced mechanical allodynia and hyperalgesia, which was assessed 30 min after EA using von Frey filaments. Beginning on day 13, the response frequency to von Frey filaments (4-15 g) was significantly increased in paclitaxel-injected rats compared to those injected with vehicle. EA at 10 Hz significantly (P<0.05) decreased response frequency at 4-15 g compared to sham EA; EA at 100 Hz only decreased response frequency at 15 g stimulation. Compared to sham EA plus vehicle, EA at 10 Hz plus either a μ, δ, or κ opioid receptor antagonist did not significantly decrease mechanical response frequency, indicating that all three antagonists blocked EA inhibition of allodynia and hyperalgesia. Since we previously demonstrated that μ and δ but not κ opioid receptors affect EA anti-hyperalgesia in an inflammatory pain model, these data show that EA inhibits pain through different opioid receptors under varying conditions. Our data indicate that EA at 10 Hz inhibits mechanical allodynia/hyperalgesia more potently than does EA at 100 Hz. Thus, EA significantly inhibits paclitaxel-induced allodynia/hyperalgesia through spinal opioid receptors, and EA may be a useful complementary treatment for neuropathic pain patients.