Extract of Triticum aestivum Sprouts Suppresses Acetaminophen-Induced Hepatotoxicity in Mice by Inhibiting Oxidative Stress.

Wheat (Triticum aestivum L.) is the oldest known food crop, and many studies have reported that wheat shoots (i.e., wheatgrass) possess anti-cancer, anti-inflammatory, and antioxidant activities. However, the potentially ameliorative effect of wheat shoots on hepatotoxicity caused by high doses of N-acetyl-para-aminophenol (acetaminophen, APAP) has yet to be reported. C57BL/6 mice received daily oral TAE (100 or 200 mg/kg), positive control (silymarin 100 mg/kg), or negative control (saline vehicle) treatments for 7 days prior to intraperitoneal APAP injection. Histological, serum (ELISA), Western blotting, and quantitative PCR analyses of excised liver tissues were then performed. Pre-treatment with TAE (100 or 200 mg/kg) ameliorated APAP-induced pathological damage (i.e., hepatotoxic lesions), reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and also ameliorated APAP-induced increases in oxidative stress, thereby inhibiting oxidative liver damage and reducing the expression of inflammatory cytokines. In addition, TAE pre-treatment inhibited the expression of Cytochrome P4502E1 (CYP2E1), which is a key enzyme in the onset of APAP-induced hepatotoxicity, suppressed the expression of the target proteins regulated by the antioxidant enzyme Nrf2, and suppressed hepatocyte apoptosis. These findings suggest that TAE is an attractive therapeutic candidate that exhibits potential hepatoprotective activity by inhibiting oxidative stress, inflammation, apoptosis, and liver damage.

The spinal antinociceptive mechanism determined by systemic administration of BD1047 in zymosan-induced hyperalgesia in rats.

Although sigma-1 receptor (Sig-1R) antagonists have a potential antinociceptive effect in inflammatory diseases, the precise mechanism is not fully understood. The present study was aimed to elucidate the role of spinal neurons and microglia in the anti-nociceptive mechanism of BD1047 (a prototypical Sig-1R antagonist) using an inflammatory pain model based on intraplantar injection of zymosan. Oral pretreatment with BD1047 dose-dependently reduced zymosan-induced thermal and mechanical hyperalgesia as well as spinal neuronal activation including increased immunoreactivity of Fos, protein kinase C (PKC) and 'PKC-dependent phosphorylation of the NMDA receptor subunit 1' (pNR1). Zymosan also led to increased CD11b immunoreactivity (a marker of microglia) accompanied by 'phosphorylated p38 mitogen activated protein kinase' (p-p38MAPK) and interleukin-1ßimmunoreactivity in the spinal dorsal horn. Intrathecal injection of a microglia modulator (minocycline), p38MAPK inhibitor (SB203580) or interleukin-1ßneutralizing antibody significantly attenuated zymosan-induced hyperalgesia. Specifically, oral pretreatment with BD1047 reduced the immunoreactivity of CD11b, p-p38MAPK and interleukin-1ß. In the spinal cord section, Sig-1R immunoreactivity was exclusively distributed in both spinal dorsal horn neurons and central endings of unmyelinated primary afferent fibers but not in glia. Intrathecal injection of BD1047 alleviated zymosan-induced hyperalgesia up to the level of oral administration. Taken together, our data imply that antinociceptive effect induced by oral treatment with BD1047 may be mediated, at least in part, by the inhibition of neuronal and microglial activation in the spinal cord triggered by inflammatory conditions.

Protective Effect of Ginsenoside Rb1 on Hydrogen Peroxide-induced Oxidative Stress in Rat Articular Chondrocytes.

The abnormal maturation and ossification of articular chondrocytes play a central role in the pathogenesis of osteoarthritis (OA). Inhibiting the enzymatic degradation of the extracellular matrix and maintaining the cellular phenotype are two of the major goals of interest in managing OA. Ginseng is frequently taken orally, as a crude substance, as a traditional medicine in Asian countries. Ginsenoside Rb1, a major component of ginseng that contains an aglycone with a dammarane skeleton, has been reported to exhibit various biological activities, including anti-inflammatory and anti-tumor effects. However, a chondroprotective effect of ginsenoside Rb1 related to OA has not yet been reported. The purpose of this study was to demonstrate the chondroprotective effect of ginsenoside Rb1 on the regulation of pro-inflammatory factors and chondrogenic genes. Cultured rat articular chondrocytes were treated with 100 µM ginsenoside Rb1 and/or 500 µM hydrogen peroxide (H2O2) and assessed for viability, reactive oxygen species production, nitric oxide (NO) release, and chondrogenic gene expression. Ginsenoside Rb1 treatment resulted in reductions in the levels of pro-inflammatory cytokine and NO in H2O2-treated chondrocytes. The expression levels of chondrogenic genes, such as type II collagen and SOX9, were increased in the presence of ginsenoside Rb1, whereas the expression levels of inflammatory genes related to chondrocytes, such as MMP1 and MMP13, were reduced by approximately 50%. These results suggest that ginsenoside Rb1 has potential for use as a therapeutic agent in OA patients.

Anti-inflammatory effects of [6]-shogaol: potential roles of HDAC inhibition and HSP70 induction.

Ginger extracts have been reported to have anti-inflammatory, anti-oxidant, and anti-cancer effects. [6]-shogaol is one of the most bioactive components of ginger rhizomes. This study assessed the [6]-shogaol's ability to protect cultured primary rat astrocytes against lipopolysaccharide (LPS)-induced inflammation. [6]-shogaol was shown to suppress the release of pro-inflammatory cytokines and decreased the level of inducible nitric oxide syntheses (iNOS), cyclooxygenase-2 (COX-2), and phospho-NF-kB in LPS-treated astrocytes. Furthermore, [6]-shogaol treatment markedly up-regulated histone H3 acetylation and suppressed histone deacetylase (HDAC)1 expression. In addition, [6]-shogaol treatment also increased the expression of heat-shock protein (HSP)70. The neuroprotective, neurotrphic, and anti-inflammatory properties of [6]-shogaol may be translated to improvements in neurological performance. [6]-Shogaol's ability to inhibit HDAC was comparable to that of commonly used HDAC inhibitors Trichostatin A and MS275. Taken together, our results suggest that [6]-shogaol can significantly attenuate a variety of neuroinflammatory responses by inducing HSP70, that is associated with HDAC inhibition in cortical astrocytes.

Effect of bee venom acupuncture on methamphetamine-induced hyperactivity, hyperthermia and Fos expression in mice.

Acupuncture has been used to treat drug addiction by nicotine, alcohol, cocaine and morphine. This study was designed to investigate the effect of bee venom (BV) acupuncture on hyperactivity and hyperthermia induced by acute exposure to methamphetamine (METH, 1mg/kg, s.c.) in mice. Diluted BV (20µl of 0.01, 0.1, 1 and 10mg/ml in saline, s.c.) was administered bilaterally into the Zusanli acupoint (ST36) or control points (SP9 or GB39 or tail base). BV injection into ST36 dose dependently reduced METH-induced hyperactivity and hyperthermia, while BV injection (1mg/ml) into control points did not produce these suppressive effects. METH injection significantly increased Fos expression in several brain regions including nucleus accumbens (NA), caudate putamen (CPU), ventral tegmental area (VTA), substantia nigra (SN) and locus coeruleus (LC). Interestingly, BV (1mg/ml) injection into ST36 further increased METH-induced Fos expression in NA (core and shell), SN and LC. When we performed sciatic denervation or combination treatment of BV and lidocaine (BV diluted in 5% lidocaine solution), the enhancement of Fos elevation by BV was completely blocked in the NA, SN and LC in METH-injected mice, indicating that BV-induced peripheral nerve stimulation played an important role in the BV effect. Furthermore, the effects of BV were completely blocked by the α2-adrenoceptor antagonist, idazoxan (3mg/kg, i.p.), but not by ß-adrenoceptor antagonist, propranolol (10mg/kg, i.p.). Taken together, these findings suggest that BV acupuncture into ST36 may modulate METH-induced hyperactivity, hyperthermia and Fos expression through activation of the peripheral nerve and the central α2-adrenergic activation.

Acupoint stimulation with diluted bee venom (apipuncture) potentiates the analgesic effect of intrathecal clonidine in the rodent formalin test and in a neuropathic pain model.

UNLABELLED: Although intrathecal (i.t.) administration of the alpha(2)-adrenoceptor agonist clonidine has a pronounced analgesic effect, the clinical use of clonidine is limited by its side effects. Previously, our laboratory has demonstrated that the subcutaneous injection of diluted bee venom (DBV) into an acupoint (termed apipuncture) produces significant analgesic effect in various pain animal models. The present study was designed to examine whether DBV injection into the Zusanli acupoint (ST-36) could enhance lower-dose clonidine-induced analgesic effects without the development of hypotension, bradycardia, or sedation. In the mouse formalin test, DBV injection produced a dramatic leftward shift in the dose-response curve for clonidine-induced analgesia. In a rat neuropathic pain model i.t. clonidine dose dependently suppressed chronic constriction injury (CCI)-induced mechanical allodynia and thermal hyperalgesia, and this clonidine-induced analgesic effect was significantly potentiated by apipuncture pretreatment. DBV apipuncture alone or in combination with a low dose of i.t. clonidine produced an analgesic effect similar to that of the high dose of clonidine, but without significant side effects. The analgesic effect produced by the combination of i.t. clonidine and apipuncture was completely blocked by pretreatment with an alpha(2)-adrenoceptor antagonist. These data show that DBV-apipuncture significantly enhances clonidine-induced analgesia and suggest that a combination of low dose clonidine with acupuncture therapy represents a novel strategy for pain management that could eliminates clonidine's side effects. PERSPECTIVE: This study demonstrated that intrathecal clonidine-induced analgesia is significantly enhanced when it is combined with chemical acupuncture treatment. The administration of low-dose clonidine in combination with acupuncture produced a potent analgesic effect without significant side effects and thus represents a potential novel strategy for the management of chronic pain.

The anti-arthritic effect of ursolic acid on zymosan-induced acute inflammation and adjuvant-induced chronic arthritis models.

Ursolic acid (UA) is pentacyclic triterpenoic acid that naturally occurs in many medicinal herbs and plants. In this study, we examined the possible suppressive effect of UA extracted from Oldenlandia diffusa on zymosan-induced acute inflammation in mice and complete Freund's adjuvant (CFA)-induced arthritis in rats. UA treatment (per oral) dose-dependently (25-200 mg kg(-1)) suppressed zymosan-induced leucocyte migration and prostaglandin E2 (PGE(2)) production in the air pouch exudates. Since the maximal effective dose of UA was 50 mg kg(-1) in the zymosan experiment, we used this dose of UA in a subsequent study using an adjuvant-induced rheumatoid arthritis model. UA treatment (50 mg kg(-1), per oral, once a day for 10 days) was started from day 12 after adjuvant injection. UA dramatically inhibited paw swelling, plasma PGE(2) production and radiological changes in the joint caused by CFA injection. Moreover, UA significantly suppressed the arthritis-induced mechanical and thermal hyperalgesia as well as the spinal Fos expression, as determined by immunohistochemistry, which was increased by CFA injection. In addition, overall anti-arthritic potency of UA was comparable with ibuprofen (100 mg kg(-1), oral) while UA did not induce significant gastric lesions as compared with the ibuprofen treatment group. These findings strongly suggest that UA is a useful suppressive compound for rheumatoid arthritis treatment with low risk of gastric problems.

Low-frequency electroacupuncture suppresses carrageenan-induced paw inflammation in mice via sympathetic post-ganglionic neurons, while high-frequency EA suppression is mediated by the sympathoadrenal medullary axis.

Although the frequency-dependent antinociceptive mechanisms of electroacupuncture (EA) have been well demonstrated, the anti-inflammatory mechanisms that underlie the suppressive effects induced by different frequencies of EA stimulation on peripheral inflammation are largely unknown. We have previously reported that EA stimulation can activate the sympathetic nervous system (SNS) and that this activation is responsible for the EA-induced suppression of zymosan-induced leukocyte migration. The present study was designed to evaluate the differential effect of low (1Hz, LF EA) versus high (120Hz, HF EA) frequency EA stimulation on SNS activation and ultimately on carrageenan-induced inflammation. Immediately after carrageenan injection, we applied either LF EA or HF EA bilaterally to the Zusanli (ST36) acupoints. To evaluate the anti-inflammatory effect of EA (EA-AI), paw volume and myeloperoxidase (MPO) activity, a marker of infiltrated leukocytes, were measured and the paw withdrawal latency to noxious heat stimulation was also assessed. Both LF EA and HF EA significantly suppressed the carrageenan-induced paw edema and MPO activity. Moreover, thermal hyperalgesia was strongly attenuated in both the LF EA and HF EA groups. Adrenalectomy significantly diminished HF EA-AI without affecting LF EA-AI. Pretreatment with the corticosterone receptor antagonist, RU-486 did not affect either LF EA- or HF EA-AI. On the other hand, administration of 6-hydroxydopamine (a neurotoxin for peripheral sympathetic nerve endings) selectively blocked LF EA-AI. Propranolol (a beta-adrenoceptor antagonist) completely abolished both LF EA- and HF EA-AI. The results of this study suggest that the suppressive effects of LF EA on carrageenan-induced paw inflammation are mediated by sympathetic post-ganglionic neurons, while the suppressive effects of HF EA are mediated by the sympatho-adrenal medullary axis.

Bee venom injection produces a peripheral anti-inflammatory effect by activation of a nitric oxide-dependent spinocoeruleus pathway.

Our recent data, obtained using a zymosan-induced inflammatory air pouch model in mice, have demonstrated that subcutaneous bee venom (BV) injection into the hind limb selectively activates the contralateral brain stem locus coeruleus (LC) and then via a descending noradrenergic pathway and subsequent adrenal medullary catecholamine release induces a potent anti-inflammatory effect. While the efferent limb of this BV-induced neuroimmune anti-inflammatory pathway is well documented, the afferent limb of this pathway is poorly understood. In particular the spinal mechanisms involved with BV activation of the LC are currently unknown. Spinal nitric oxide (NO) and its synthase (NOS) have been shown to play an important role in the transmission and amplification of neuronal information from the spinal cord to the brain stem. In the present study we evaluated whether spinal NO plays a role in BV-induced LC activation, since we have previously shown that LC activation underlies this 'BV-induced anti-inflammatory effect' (BVAI) using the mouse air pouch model. Intrathecal (i.t.) pretreatment with l-nitro arginine methyl ester (l-NAME, non-selective NOS inhibitor), hemoglobin (NO scavenger) or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, soluble guanylate cyclase inhibitor) abolished BVAI on zymosan-induced leukocyte migration into the air pouch. Moreover, i.t. injection of l-N-iminoethyl-lysine (l-NIL, inducible NOS inhibitor), but not 7-nitroindazole (7-NI, neuronal NOS inhibitor), also inhibited BVAI. BV injection significantly increased both the number of Fos immunoreactive neurons and tyrosine hydroxylase-Fos double labeling neurons in the contralateral LC in zymosan-induced inflamed mice. Importantly this increase in Fos expression in the LC was also completely inhibited by i.t. injection of l-NIL, but not by i.t. injection of 7-NI. Collectively these results indicate that spinal NO generated from inducible NOS is involved in the BV-induced LC activation that underlies BVAI.

Low-frequency electroacupuncture suppresses zymosan-induced peripheral inflammation via activation of sympathetic post-ganglionic neurons.

Electroacupuncture (EA) is used to treat a variety of inflammatory diseases; however, the neurophysiological mechanisms underlying EA's anti-inflammatory effect remain unclear. Accumulating evidence suggests that the sympathetic nervous system regulates immunologic and inflammatory responses and thus we hypothesized that this system could be involved in EA's anti-inflammatory effect (EA-AI). The goal of the present study was to evaluate whether the sympathetic nervous system plays a critical role in EA-AI using a mouse air pouch inflammation model. We found that bilateral low-frequency (1 Hz) EA applied to the Zusanli acupoint significantly suppressed the number of zymosan-induced leukocytes migrating into the air pouch. Furthermore, double-labeling immunohistochemical experiments showed that EA stimulation increased Fos expression in choline acetyltransferase (ChAT)-positive sympathetic pre-ganglionic neurons in the intermediolateral region of thoracic spinal cord segments. Chemical sympathetic denervation by intraperitoneal injection of 6-hydroxydopamine (which spares sympathetic adrenal medullary innervation) significantly inhibited EA-AI. In contrast, adrenalectomy did not alter EA-AI. Finally, systemic propranolol administration significantly inhibited EA's anti-inflammatory effect, suggesting that beta-adrenoceptors are involved. Collectively, these results suggest that EA produces an anti-inflammatory effect in this mouse air pouch model by activating the sympathetic nervous system leading to the release of catecholamines from post-ganglionic nerve terminals, which act on beta-adrenoceptors on immune cells to inhibit their migration.

Bee venom injection significantly reduces nociceptive behavior in the mouse formalin test via capsaicin-insensitive afferents.

UNLABELLED: Peripheral bee venom (BV) administration produces 2 contrasting effects, nociception and antinociception. This study was designed to evaluate whether the initial nociceptive effect induced by BV injection into the Zusanli acupoint is involved in producing the more prolonged antinociceptive effect observed in the mouse formalin test, and whether capsaicin-sensitive primary afferents are involved in these effects. BV injection into the Zusanli point increased spinal Fos expression but not spontaneous nociceptive behavior. BV pretreatment 10 minutes before intraplantar formalin injection dose-dependently attenuated nociceptive behavior associated with the second phase of the formalin test. The destruction of capsaicin-sensitive primary afferents by resiniferatoxin (RTX) pretreatment selectively decreased BV-induced spinal Fos expression but did not affect BV-induced antinociception. Furthermore, BV injection increased Fos expression in tyrosine hydroxylase immunoreactive neurons in the locus caeruleus, and this expression was unaltered by RTX pretreatment. Finally, BV's antinociception was blocked by intrathecal injection of 10 microg idazoxan, and this effect was not modified by RTX pretreatment. These findings suggest that subcutaneous BV stimulation of the Zusanli point activates central catecholaminergic neurons via capsaicin-insensitive afferent fibers without induction of nociceptive behavior. This in turn leads to the activation of spinal alpha2-adrenoceptors, which ultimately reduces formalin-evoked nociceptive behaviors. PERSPECTIVE: This study demonstrates that BV acupuncture produces a significant antinociception without nociceptive behavior in rodents, which is mediated by capsaicin-insensitive afferents and involves activation of central adrenergic circuits. These results further suggest that BV stimulation into this acupuncture point might be a valuable alternative to traditional electrical or mechanical acupoint stimulation.

Substantial role of locus coeruleus-noradrenergic activation and capsaicin-insensitive primary afferent fibers in bee venom's anti-inflammatory effect.

Several lines of evidence indicate significant interactions between the immune and nervous systems. Our recent study reveals that 'bee venom (BV) induced anti-inflammatory effect' (BVAI) was produced by sympathetic preganglionic neuronal activation and subsequent adrenomedullary catecholamine release in a zymosan-induced inflammation model. However, the specific peripheral input and the supraspinal neuronal systems that are involved in this BVAI remain to be defined. Here we show that subcutaneous BV injection into left hind limb significantly reduces zymosan-induced leukocyte migration and that this effect is completely inhibited by denervation of the left sciatic nerve. This BVAI was not affected by the destruction of capsaicin-sensitive primary afferent fibers using either neonatal capsaicin or resiniferatoxin (RTX) pretreatment. BV injection into the left hind limb significantly increased Fos expression in the contralateral locus coeruleus (LC) in non-inflamed mice. In zymosan-inflamed mice, BV injection produced a further increase in LC Fos expression as compared with non-inflamed mice. This BV-induced Fos increase in the LC was not affected by RTX pretreatment. Pharmacological blockage of central noradrenergic activity by either central chemical sympathectomy (i.c.v. 6-hydroxydopamine) or alpha2 adrenoceptor antagonism (i.c.v. idazoxan) completely blocked BVAI. Taken together, these results suggest that BVAI is mediated by peripheral activation of capsaicin-insensitive primary afferent fibers and subsequent central noradrenergic activation including the LC.

The anti-inflammatory effects of low- and high-frequency electroacupuncture are mediated by peripheral opioids in a mouse air pouch inflammation model.

BACKGROUND: Although acupuncture has been widely used for complementary therapeutic approaches to treat inflammatory diseases and inflammation-induced pain, the potential anti-inflammatory effects of acupuncture treatment remain controversial in clinical trials, and the underlying mechanisms are still unclear. OBJECTIVE: The objective was to determine whether electroacupuncture (EA) is able to suppress the peripheral inflammatory response (e.g., zymosan-induced leukocyte migration into air pouch). As part of a mechanistic approach, it was further evaluated whether endogenous opioid systems are involved in the "EA-induced anti-inflammatory effect" (EA-AI). METHODS: EA (1 or 120 Hz) was performed bilaterally in the Zusanli acupoint (ST36) or in a nonacupoint (gluteal muscle) for 30 min in ICR mice under anesthetic condition. The number of leukocytes that migrated into the air pouch was counted 4 hours after zymosan injection. EA was performed at 0, 0.5, 1, or 2 hours prior to zymosan injection, respectively. To evaluate opioid involvement in EA-AI, intrathecal naloxone (36 microg/mouse) and intraperitoneal naloxone methiodide (30 mg/kg) were administered 10 min before EA stimulation. RESULTS: Both the 1 and 120 Hz frequencies of EA into Zusanli acupoint at the same time with zymosan injection significantly reduced leukocyte migration into the air pouch as compared with those of control groups (i.e., anesthetic control and needling control into Zusanli acupoint without electrical stimulation). The EA stimulation into nonacupoint did not produce any significant anti-inflammatory effect. EA treatment at 0.5 hours prior to zymosan injection also produced an anti-inflammatory effect but 1 and 2 hours prior to zymosan injection did not elicit any effect. Peripheral opioid blockage significantly reversed EA-AI, whereas spinal opioid blockage did not alter EA-AI. CONCLUSION: EA can suppress peripheral inflammation through a peripheral opioid mechanism. To achieve the full effectiveness of EA, repeated application is recommended for the treatment of a variety of inflammatory diseases.

Water soluble fraction (<10 kDa) from bee venom reduces visceral pain behavior through spinal alpha 2-adrenergic activity in mice.

We have previously shown that subcutaneous bee venom (BV) injection reduces visceral pain behavior in mice, but it is not clear which constituent of BV is responsible for its antinociceptive effect. In the present study, we now demonstrate that a water-soluble subfraction of BV (BVA) reproduces the antinociceptive effect of BV in acetic acid-induced visceral pain model. We further evaluated three different BVA subfractions that were separated by molecular weight, and found that only the BVAF3 subfraction (a molecular weight of <10 kDa) produced a significant antinociceptive effect on abdominal stretches and suppressed visceral pain-induced spinal cord Fos expression. Injection of melittin (MEL), a major constituent of BVAF3, also produced a visceral antinociception. However, melittin's antinociception was completely blocked by boiling for 10 min at 100 degrees C, while boiling either whole BV or BVAF3 did not prevent their antinociception. The antinociceptive effect of BVAF3 was completely blocked by intrathecal pretreatment with the alpha2-adrenoceptor antagonist, yohimbine (YOH), while intrathecal pretreatment with the opioid antagonist, naloxone (NAL) or the serotonin antagonist, methysergide, had no effect. These data demonstrate that BVAF3 is responsible for the visceral antinociception of whole BV and further suggest that this effect is mediated in part by spinal alpha2-adrenergic activity.

Antinociceptive mechanisms associated with diluted bee venom acupuncture (apipuncture) in the rat formalin test: involvement of descending adrenergic and serotonergic pathways.

In a previous report, subcutaneous injection of diluted bee venom (dBV) into a specific acupuncture point (Zusanli, ST36), a procedure termed apipuncture, was shown to produce an antinociceptive effect in the rat formalin pain model. However, the central antinociceptive mechanisms responsible for this effect have not been established. Traditional acupuncture-induced antinociception is considered to be mediated by activation of the descending pain inhibitory system (DPIS) including initiation of its opioidergic, adrenergic and serotonergic components. The purpose of the present study was to investigate whether the antinociceptive effect of apipuncture is also mediated by the DPIS. Behavioral experiments verified that apipuncture significantly reduces licking behavior in the late phase of formalin test in rats. This antinociceptive effect of apipuncture was not modified by intrathecal pretreatment with naltrexone (a non-selective opioid receptor antagonist), prazosin (an alpha1 adrenoceptor antagonist) or propranolol (an beta adrenoceptor antagonist). In contrast, intrathecally injected idazoxan (an alpha2 adrenoceptor antagonist) or intrathecal methysergide (a serotonin receptor antagonist) significantly reversed apipuncture-induced antinociception. These results suggest that apipuncture-induced antinociception is produced by activation of alpha2 adrenergic and serotonergic components of the DPIS.

Electroacupuncture ameliorates experimental colitis induced by acetic acid in rat.

The effect of electroacupuncture (EA) on experimental colitis was investigated in Sprague-Dawley rats. Colitis was induced by intracolonic instillation of 4% acetic acid. EA (2 Hz, 0.05 ms, 2 V for 20 min) was applied to bilateral Hoku (LI-4) and Zusanli (ST-36) on 12 hrs and 36 hrs after induction of colitis. EA-treatment significantly reduced the macroscopic damage and the myeloperoxidase activity of colonic samples at 3 days post-induction of colitis. Colitic colon showed a decreased in vitro motility. However, colonic motility of EA-treated group was not significantly different from that of normal group. The anti-inflammatory effect of EA was not inhibited by a glucocorticoid receptor antagonist, RU-486, but suppressed by a beta-adrenoceptor antagonist, propranonol. These results suggest that EA-treatment has a beneficial effect on colitis, and its anti-inflammatory effect is mediated by beta-adrenoceptor activation but not by endogenous glucocorticoiddependent mechanism.

Acupoint stimulation with diluted bee venom (apipuncture) alleviates thermal hyperalgesia in a rodent neuropathic pain model: involvement of spinal alpha 2-adrenoceptors.

UNLABELLED: Chemical acupuncture with diluted bee venom (DBV), termed apipuncture, has been traditionally used in oriental medicine to treat several inflammatory diseases and chronic pain conditions. In the present study we investigated the potential antihyperalgesic and antiallodynic effects of apipuncture in a rat neuropathic pain model. DBV (0.25 mg/kg, subcutaneous) was injected into the Zusanli acupoint 2 weeks after chronic constrictive injury (CCI) of the sciatic nerve. Between 5 and 45 minutes after DBV injection, we observed a significant reduction in the thermal hyperalgesia induced by CCI, but apipuncture failed to reduce CCI-induced mechanical allodynia. We subsequently examined whether this antihyperalgesic effect of apipuncture was related to the activation of spinal opioid receptors and/or alpha2-adrenoceptors. Intrathecal pretreatment with naloxone (10 microg/rat), an opioid receptor antagonist, did not reverse the antihyperalgesic effect of apipuncture, whereas pretreatment with idazoxan (40 microg/rat), an alpha2-adrenoceptor antagonist, completely blocked the effect of apipuncture. These results indicate that DBV-induced apipuncture significantly reduces the thermal hyperalgesia generated by CCI and also suggest that this antihyperalgesic effect is dependent on the activation of alpha2-adrenoceptors, but not opioid receptors, in the spinal cord. PERSPECTIVE: The antinociceptive effect of apipuncture was evaluated in a rodent neuropathic pain model. The relieving effect of apipuncture on thermal hyperalgesia was found to be mediated by spinal alpha2-adrenoceptors, but not opioid receptors. These data suggest that apipuncture might be an effective alternative therapy for patients with painful peripheral neuropathy, especially for those who are poorly responsive to opioid analgesics.

Bee venom acupoint stimulation increases Fos expression in catecholaminergic neurons in the rat brain.

Fos immunocytochemistry was combined with tyrosine hydroxylase (TH) or dopamine-beta-hydroxylase (DBH) immunolabeling to examine brainstem catecholaminergic neuronal activation resulting from bee venom (BV) stimulation of the Zusanli acupoint (ST36) in Sprague-Dawley rats. BV injection into the Zusanli acupoint caused increased Fos expression in catecholaminergic neurons located in the hypothalamic arcuate nucleus (Arc), the dorsal raphe (DR), the A5 cell group (A5) and the locus coeruleus (LC). BV acupoint stimulation significantly increased Fos-TH double-labeled neurons in the Arc, LC and DR. Fos-DBH positive neurons were also increased by BV acupoint stimulation in the LC and A5. In contrast BV stimulation of a non-acupoint only increased Fos expression and Fos-TH double-labeled neurons in the Arc. These data indicate that BV acupoint stimulation activates brainstem catecholaminergic neurons and that this activation underlies BV acupoint-induced antinociception.

Acupoint stimulation using bee venom attenuates formalin-induced pain behavior and spinal cord fos expression in rats.

In two previous reports, we have demonstrated that injection of bee venom (BV) into an acupoint produces a significant antinociceptive and anti-inflammatory effect in both a mouse model of visceral nociception and a rat model of chronic arthritis. The present study was designed to evaluate the potential antinociceptive effect of BV pretreatment on formalin-induced pain behavior and it associated spinal cord Fos expression in rats. Adult Sprague-Dawley rats were injected with BV directly into the Zusanli (ST36) acupoint or into an arbitrary non-acupoint located on the back. BV pretreatment into the Zusanli acupoint significantly decreased paw-licking time in the late phase of the formalin test. In contrast, BV injected into a non-acupoint in the back region did not suppress the paw-licking time. In addition, BV pretreatment into the Zusanli acupoint markedly inhibited spinal cord Fos expression induced by formalin injection. These findings indicate that BV pretreatment into the Zusanli acupoint has an antinociceptive effect on formalin-induced pain behavior.

The water-soluble fraction of bee venom produces antinociceptive and anti-inflammatory effects on rheumatoid arthritis in rats.

We recently demonstrated that bee venom (BV) injection into the Zusanli acupoint produced a significantly more potent anti-inflammatory and antinociceptive effect than injection into a non-acupoint in a Freund's adjuvant induced rheumatoid arthritis (RA) model. However, the precise BV constituents responsible for these antinociceptive and/or anti-inflammatory effects are not fully understood. In order to investigate the possible role of the soluble fraction of BV in producing the anti-arthritic actions of BV acupuncture, whole BV was extracted into two fractions according to solubility (a water soluble fraction, BVA and an ethylacetate soluble fraction, BVE) and the BVA fraction was further tested. Subcutaneous BVA injection (0.9 mg/kg/day) into the Zusanli acupoint was found to dramatically inhibit paw edema and radiological change (i.e. new bone proliferation and soft tissue swelling) caused by Freund's adjuvant injection. BVA treatment also reduced the increase in serum interleukin-6 caused by RA induction to levels observed in non-arthritic animals. In addition, BVA therapy significantly reduced arthritis-induced nociceptive behaviors (i.e. nociceptive scores for mechanical hyperalgesia and thermal hyperalgesia). Finally, BVA treatment significantly suppressed adjuvant-induced Fos expression in the lumbar spinal cord at 3 weeks post-adjuvant injection. In contrast, BVE treatment (0.05 mg/kg/day) failed to show any anti-inflammatory or antinociceptive effects on RA. The results of the present study demonstrate that BVA is the effective fraction of whole BV responsible for the antinociception and anti-inflammatory effects of BV acupuncture treatment. Thus it is recommended that this fraction of BV be used for long-term treatment of RA-induced pain and inflammation. However, further study is necessary to clarify which constituents of the BVA fraction are directly responsible for these anti-arthritis effects.