Antinociceptive effects of systemic paeoniflorin on bee venom-induced various ‘phenotypes’ of nociception and hypersensitivity

Therapeutic effects of paeoniflorin on irritable bowel syndrome in rats

BACKGROUND

Irritable bowel syndrome (IBS) is a functional bowel disorder (FBD).

OBJECTIVES

To assess the therapeutic effects of paeoniflorin (PF) on IBS in rats.

METHOD

Sixty male Sprague-Dawley rats were randomly divided into normal, model, positive drug, low-dose PF, medium-dose PF and high-dose PF groups (n = 10). After gavage for 2 consecutive weeks, the effect of PF on abdominal pain symptoms was assessed based on the abdominal withdrawal reflex (AWR) score, fecal water content and pathological changes in colon tissues. D-lactate, interleukin-1β (IL-1β), transforming growth factor-β (TGF-β) and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay, and phosphorylated nuclear factor kappa B (p-NF-κB) p65 was detected by Western blotting. The abundance and diversity changes of intestinal flora were explored using 16S ribosomal RNA sequencing.

RESULT

In PF groups, the mucosal morphology of colon tissues was intact, and the glands were arranged neatly and structured clearly, without obvious inflammatory cell infiltration. Compared with the model group, PF groups had significantly elevated pain threshold, and mRNA and protein levels of zonula occludens-1 (ZO-1) and occludin, decreased AWR score at 20 mmHg pressure, fecal water content, mRNA levels of IL-1β, TGF-β, and TNF-α, protein level of p-NF-κB p65 and level of serum D-lactate, and reduced levels of serum IL-1β, TGF-β, and TNF-α (p < 0.05, p < 0.01). PF groups had higher abundance of Lactobacillus, Akkermansia, Alistipes, and Bacteroides, but lower abundance of Desulfovibrio, Parasutterella, and Enterococcus than those of the model group.

CONCLUSIONS

PF exerts therapeutic effects on IBS in rats probably by regulating the intestinal flora, and then up-regulating the expressions of ZO-1 and occludin in colon tissue while down-regulating the levels of IL-1β, TGF-β, TNF-α, D-lactate and p-NF-κB p65.

A review for the pharmacological effects of paeoniflorin in the nervous system

Paeoniflorin, a terpenoid glycoside compound extracted from Paeonia lactiflora Pall, shows preventive and therapeutic effects in various types of nervous system disorders. However, to date, no comprehensive knowledge on the pharmacological effects of paeoniflorin on the nervous system is available online. Clarification of this issue may be useful for the development of paeoniflorin as a new drug for the treatment of nervous system disorders. To this end, the authors summarize the pharmacological aspects of paeoniflorin and its possible mechanisms, such as restoration of mitochondrial function; inhibition of neuroinflammation, oxidative stress, and cellular apoptosis; activation of adenosine A1 receptor, cAMP response element-binding protein (CREB) and extracellular signal-regulated kinase 1/2 (ERK1/2); or enhancement of brain-derived neurotrophic factor and serotonin function, in the prevention of disorders such as cerebral ischemia, subarachnoid hemorrhage, vascular dementia, Alzheimer's disease, Parkinson's disease, depression, post-traumatic syndrome disorder, and epilepsy, by reviewing the previously published literature.

Paeoniflorin Ameliorates Hyperprolactinemia-Induced Inhibition of Osteoblastogenesis by Suppressing the NF-κB Signaling Pathway

Hyperprolactinemia is a common endocrine disease in women of reproductive age. Research has shown that patients with hyperprolactinemia often have decreased bone mineral density and an increased risk of fractures. However, there is still a lack of effective treatments. Paeoniflorin, one of the primary bioactive components in peony, is widely used in traditional Chinese medicine. Research has shown that paeoniflorin promotes osteoblast differentiation. However, whether paeoniflorin plays a role in hyperprolactinemia-induced osteoblastogenesis inhibition is not yet clear. In this study, we investigated the effect of paeoniflorin on prolactin (PRL)-mediated inhibition of osteoblast function. Our results showed that prolactin significantly reduced the expression of alkaline phosphatase (ALP), Osterix, and runt-related transcription factor 2 (RUNX2) in MC3T3-E1 cells cultured in an osteoblast differentiation medium, suggesting that prolactin inhibited osteoblast function. After treatment with paeoniflorin (PF), the expression of these osteoblast markers was upregulated. In addition, our findings proved that paeoniflorin increased the absorbance values of ALP-positive cells and the areas of alizarin red S (ARS) deposition compared to those in the prolactin group, suggesting that paeoniflorin reversed the PRL-induced reduction in osteoblast differentiation. The PRL-induced activation of nuclear factor kappa B (NF-κB) was significantly reversed by paeoniflorin, indicating that paeoniflorin promoted osteoblast function by inhibiting the NF-κB signaling pathway. In summary, these results showed that paeoniflorin alleviated the inhibitory effect of prolactin on osteoblastogenesis by suppressing the NF-κB signaling pathway.

Effects of Danggui-Shaoyao-San on depression- and anxiety-like behaviors of rats induced by experimental tooth movement

PURPOSE

To investigate the effects of Danggui-Shaoyao-San (DSS) on depression- and anxiety-like behavior induced by experimental tooth movement (ETM) in rats.

MATERIALS AND METHODS

Thirty-six rats were randomly divided into a sham group (n = 12; rats underwent all operation procedures, except placement of orthodontic forces, and received saline treatment), ETM group (n = 12; rats received saline treatment and ETM), and DETM group (n = 12; rats received DSS [dose: 150 mg/kg twice daily from preoperative day 5 to postoperative day 7] treatment and ETM). The vacuous chewing movement (VCM) test, open-field test, and elevated plus maze test were performed to assess the depression- and anxiety-like behaviors of the rats.

RESULTS

DSS pretreatment significantly decreased the ETM-induced VCM time (P < 0.05, DETM vs. ETM), increased the ETM-induced time to the central area of experimental device during the 5 min open-field test (P < 0.05, DETM vs. ETM), and increased the ratio of time spent in the open arms of the 5 min elevated plus maze test induced by ETM (P < 0.01, DETM vs. ETM).

CONCLUSIONS

DSS pretreatment can restore the impaired abilities of rats caused by ETM-induced depression- and anxiety-like behavior.

Potential protective roles of phytochemicals on glutamate-induced neurotoxicity: A review

Glutamate, as an essential neurotransmitter, has been thought to have different roles in the central nervous system (CNS), including nerve regeneration, synaptogenesis, and neurogenesis. Excessive glutamate causes an up-regulation of the multiple signaling pathways, including phosphoinositide-3 kinase/protein kinase B (PI3K/Akt), Akt/mammalian target of rapamycin (mTOR) protein, mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK)1/2, and autophagy that are involved in neurodegenerative diseases pathophysiology. There are numerous findings on curcumin, astaxanthin, thymoquinone, and berberine, as natural products, which have outstanding effects in cell signaling far beyond their anti-oxidant activity, considering as a potential therapeutic target for glutamate excitotoxicity. Herein, we address the role of glutamate as a potential target in neurodegenerative diseases and discuss the protective effects of certain phytochemicals on glutamate-induced neurotoxicity.

A review for the anti-inflammatory effects of paeoniflorin in inflammatory disorders

Inflammatory disorders result from abnormal immune response and their incidence has increased recently. Thus, there is an urgent need to discover new treatments for inflammatory disorders. In recent years, the natural products contained in Chinese herbs have attracted much attention worldwide owing to their anti-inflammatory effects. Paeoniflorin (PF) is a bioactive compound purified from the Chinese herb Paeonia lactiflora and reports have recently emerged suggesting the great potential of P. lactiflora as an agent to counter inflammatory disorders. The anti-inflammatory effects of PF have been revealed by in vitro studies and in vivo animal experiments of different inflammatory disorders, including rheumatoid arthritis, inflammatory bowel disease, psoriasis, and asthma. This review systematically describes the recent progress of studies on the mechanism of PF and its therapeutic potential in inflammatory disorders.

Diversity of endophytic fungi of Paeonia lactiflora Pallas and screening for fungal paeoniflorin producers

Endophytic fungi from Paeonia lactiflora Pallas, which is mainly distributed in China, were characterized and screened to identify those capable of producing paeoniflorin. A total of 101 isolates obtained from the roots, stems and leaves of P. lactiflora were grouped into 16 fungal taxa based on morphological traits and internal transcribed spacers sequences, indicating that endophytic fungi of P. lactiflora are abundant and diverse. The dominant endophytic fungi were Aspergillus, Alternaria and Penicillium. More fungi were recovered from leaves than from roots and stems. The similarity index was highest between the stems and leaves (0.733), followed by the roots and leaves (0.615) and the stems and roots (0.563). Analyses of the fermentation extracts of 22 endophytic fungi by high-performance liquid chromatography and mass spectrometry revealed that three strains (R12, Alternaria tenuissima; S4, Aspergillus flavus; and R17 Penicillium commune) were able to produce paeoniflorin. Among the paeoniflorin-producing fungi, the yield of paeoniflorin from A. flavus S4 was 342.4 μg/L, and this strain could be used as a candidate for the industrial production of paeoniflorin.

Neuroprotective effect of total glycosides from paeonies against neurotoxicity induced by strychnos alkaloids related to recovering the levels of neurotransmitters and neuroendocrine hormones in rat serum and brain

Semen Strychni, a classical traditional Chinese medicine, has been widely used for its anti-tumor, analgesic and anti-inflammatory angiogenesis effects. However, taking an overdose of Semen Strychni might result in extreme neurotoxicity. Strychnos alkaloids are the main toxic constituents of Semen Strychni. Total glycosides from paeonies are considered to have neuroprotective effects. In this study, twelve potential endogenous biomarkers in rat serum and brain were monitored to investigate the protective effect of total glycosides from the paeony against strychnos alkaloids-induced neurotoxicity. A sensitive liquid chromatography-tandem mass spectrometry method was developed and validated to monitor eight neurotransmitters including glutamate, γ-aminobutyric acid, acetylcholine serotonin, dopamine, norepinephrine, tryptophan and tyrosine. An enzyme-linked immunosorbent assay method was selected for determination of four neuroendocrine hormones including thyrotrophin-releasing hormone, corticotrophin-releasing hormone, antidiuretic hormone and prolactin. Results showed that continuous administration of strychnos alkaloids for 15 days caused significant changed levels of the biomarkers (especially the four neuroendocrine hormones). Meanwhile, total glycosides from paeony pretreated rats (administrated with total glycosides from the paeony for 15 days before exposure to strychnos alkaloids) showed recovered levels of these biomarkers. The results suggested that the neurotransmitters and neuroendocrine hormones in serum and brain might play potential roles as biomarkers. This study provides the possibility of alleviating the Semen Strychni-induced neurotoxicity in clinic by pre-protection with total glycosides from paeonies.

Eight neurotransmitters and four neuroendocrine hormones in rat serum and brain were quantified to investigate the neuroprotective effect of total glycosides from paeony against neurotoxicity induced by strychnos alkaloids.

Paeoniflorin regulates osteoclastogenesis and osteoblastogenesis via manipulating NF-κB signaling pathway both in vitro and in vivo

The metabolic balance between synthesis and resorption of the bone is maintained by osteoblasts and osteoclasts, respectively. Identification of agents that stimulate bone formation and suppress excessive osteoclast formation, may aid in preventing and treating conditions like osteoporosis and periprosthetic loosening. Paeoniflorin is a natural product derived from Paeonia lactiflora Pall with anti-inflammatory, analgesic, and diuretic properties. However, the effect of paeoniflorin on osteoclastogenesis and osteoblastogenesis is unknown. Herein, we demonstrated that paeoniflorin has a dose-dependent suppressive action on RANKL-evoked osteoclast differentiation and bone resorption, achieved by inhibiting the NF-κB pathway and subunit p65 nuclear translocation. Simultaneously, paeoniflorin was also found to stimulate osteoblast differentiation and bone mineralization, in addition to rescuing TNFα-impaired osteoblastogenesis. At the molecular level, paeoniflorin was found to inhibit NF-κB transcriptional activity and stimulate osteoblastogenesis-related marker gene expression (ALP, osteocalcin, OPN and Runx2), a trend that was inhibited by p65 overexpression. In ovariectomized mice, paeoniflorin was found to improve osteoblast activity, inhibit osteoclast activity, and thus, reduce ovariectomy-induced osteoporosis. Our study demonstrated that paeoniflorin simultaneously suppressed osteoclastogenesis and facilitated osteoblastogenesis by manipulating the actions of NF-κB. Therefore, paeoniflorin may serve as an ideal therapeutic antidote for osteoporosis.

Paeoniflorin ameliorates Adriamycin-induced nephrotic syndrome through the PPARγ/ANGPTL4 pathway in vivo and vitro

Paeoniflorin (PF), an effective composition that is extracted from Radix Paeoniae Alba, plays a role in protecting against various kidney diseases. However, the mechanism of PF on nephrotic syndrome (NS) remains unclear. The aim of this study was to investigate the protective role of PF on Adriamycin (ADR)-induced NS in vivo and vitro as well as its potential mechanism. In animal study, PF significantly decreased the levels of 24-h urine protein, blood urea nitrogen, serum creatinine, total cholesterol and triglycerides in NS rats, but increased the total protein and albumin levels. Hematoxylin-eosin (HE) staining revealed that the kidney lesion was resolved upon PF treatment. After treatment with PF, the morphology and number of podocytes in renal tissue were restored to normal. PF increased expression of synaptopodin and decreased expression of desmin, demonstrating a protective effect in podocyte injury. Further studies revealed that PF upregulated Peroxisome proliferator-activated receptor gamma (PPARγ) and restrained Angiopointin-like 4 (ANGPTL4) in kidney tissue. In vitro study, PF reduced Caspase3 and Bax and increased Bcl-2, indicating that the apoptosis rate of podocytes induced by ADR was reduced by PF. Furthermore, PF ameliorated podocyte injury by upregulating synaptopodin and reducing desmin. In accordance with animal study, PF downregulated ANGPTL4 by activating PPARγ. However, the therapeutic effects of PF were reversed by GW9662 (PPARγ inhibitor), likely by suppressing ANGPTL4 degradation. In general, these results demonstrate that PF has a good therapeutic effect on NS by activating PPARγ and subsequently inhibiting ANGPTL4.

Paeoniflorin prevents TLR2/4-mediated inflammation in type 2 diabetic nephropathy

Paeoniflorin is an effective Chinese traditional medicine with anti-inflammatory and immune-regulatory effects. The aim of this study was to investigate the underlying renoprotective mechanism of Paeoniflorin. In vivo, db/db mice were intraperitoneally injected with Paeoniflorin at a dose of 15, 30, or 60 mg/kg respectively. The immunostaining of TLR2, TLR4, CD68, NF-kB p65 and the mRNA level of inflammatory factors, together with the protein expression of TLR2/4 signaling were evaluated. Our data demonstrated that Paeoniflorin could decrease the urinary albumin excretion rate and inhibit macrophage infiltration and activation through blockage of the TLR2/4 signaling pathway compared with the db/db group in vivo. In vitro, RAW264.7 cells were categorized into control, bovin serum albumin (BSA)-stimulated, advanced glycation end products (AGEs)-stimulated, Paeoniflorin intervention and oxidized phospholipid (OxPAPC)-inhibited groups. The cell viability, the optimal stimulated time and concentration were measured as well as the TLR2/4 signaling activation determined by RT-PCR, Western blot and ELISA. Our data demonstrated that Paeoniflorin reduced the AGEs-induced TLR2/4 activation and inflammatory responses, which was consistent with the TLR2/4 inhibitor group. These findings indicate that Paeoniflorin prevents macrophage activation via inhibition of TLR2/4 signaling expression in type 2 diabetic nephropathy.

Paeoniflorin inhibits excitatory amino acid agonist-and high-dose morphine-induced nociceptive behavior in mice via modulation of N-methyl-D-aspartate receptors

BACKGROUND

Pain, the most common reasons for physician consultation, is a major symptom in many medical conditions that can significantly interfere with a person's life quality and general functioning. Almost all painkillers have its untoward effects. Therefore, seeking for a safe medication for pain relieve is notable nowadays. Paeonia lactiflora is a well-known traditional Chinese medicine. Paeoniflorin is an active component found in Paeonia lactiflora, which has been reported to inhibit formalin-induced nociceptive behavior in mice. Aims of this present study were to investigate effects of paeoniflorin on excitatory amino acid agonist- or high-dose morphine-induced nociceptive behaviors in mice.

RESULTS

Paeoniflorin (100, 200, 500 nmol, i.c.v.) alone and combined with glutamatergic antagonists (MK-801 14.8 pmol, or NBQX 5 nmol, i.t.) inhibited nociception. Those agents also inhibited the clonic seizure-like excitation induced by high-dose morphine (250 nmol, i.t) in mice. Antisense oligodeoxynucleotides of NMDA receptor subunits NR1, NR2A, NR2B significantly enhanced the inhibition of paeoniflorin on excitatory amino acid-and high-dose morphine-induced nociception. Docking energy data revealed that paeoniflorin had stronger binding activity in NR2A and NR2B than NR2C of NMDA receptors.

CONCLUSIONS

Results of this study indicate that paeoniflorin-induced inhibition of excitatory amino acid agonist- and high-dose morphine-induced nociceptive behaviors might be due to modulation of NMDA receptors, specifically the NR2B subunit.

Paeoniflorin exerts analgesic and hypnotic effects via adenosine A1 receptors in a mouse neuropathic pain model

RATIONAL

Neuropathic pain is frequently comorbid with sleep disturbances. Paeoniflorin, a main active compound of total glucosides of paeony, has been well documented to exhibit neuroprotective bioactivity.

OBJECTIVE

The present study evaluated effects of paeoniflorin on neuropathic pain and associated insomnia and the mechanisms involved.

METHODS

The analgesic and hypnotic effects of paeoniflorin were measured by mechanical threshold and thermal latency, electroencephalogram (EEG) and electromyogram, and c-Fos expression in a neuropathic pain insomnia model.

RESULTS

The data revealed that paeoniflorin (50 or 100 mg/kg, i.p.) significantly increased the mechanical threshold and prolonged the thermal latency in partial sciatic nerve ligation (PSNL) mice. Meanwhile, paeoniflorin increased non-rapid eye movement (NREM) sleep amount and concomitantly decreased wakefulness time. However, pretreatment with l,3-dimethy-8-cyclopenthylxanthine, an adenosine A1 receptor (R, A1R) antagonist, abolished the analgesic and hypnotic effects of paeoniflorin. Moreover, paeoniflorin at 100 mg/kg failed to change mechanical threshold and thermal latency and NREM sleep in A1R knockout PSNL mice. Immunohistochemical study showed that paeoniflorin inhibited c-Fos overexpression induced by PSNL in the anterior cingulate cortex and ventrolateral periaqueductal gray.

CONCLUSIONS

The present findings indicated that paeoniflorin exerted analgesic and hypnotic effects via adenosine A1Rs and might be of potential use in the treatment of neuropathic pain and associated insomnia.

Analgesic Effects of Danggui-Shaoyao-San on Various "Phenotypes" of Nociception and Inflammation in a Formalin Pain Model

Danggui-Shaoyao-San (DSS) is a traditional Chinese medicine, which has long been used for pain treatment and has been demonstrated to possess anti-oxidative, cognitive enhancement, and anti-depressant effects. In the present study, the effects of aqueous extracts of DSS on spontaneous pain behaviors and long-term hyperalgesia were examined to investigate the anti-nociceptive effects and underlying mechanisms. Single pretreatment of DSS dose-dependently reduced spontaneous flinches/licking time in the second, rather than the first, phase after subcutaneous injection of 5 % formalin into one hindpaw, in doses of 2.4 and 9.6 g/kg. DSS also dose-dependently inhibited FOS and cyclooxygenase-2 (COX-2) expression in both superficial and deep layers within the spinal dorsal horn. Further, DSS reduced hypoalgesia in the injected paw from 1 to 3 days and produced anti-hyperalgesic actions in both the injected paw after 3 days and non-injected paw. These data suggest involvement of enhancement of descending pain inhibition by suppression of 5-HTT levels in the spinal dorsal horn and reduction of peripheral long-term inflammation, including paw edema and ulcers. These findings suggest that DSS may be a useful therapeutic agent for short- and long-term inflammation induced pain, through both anti-inflammatory and suppression of central sensitization mechanisms.

Paeoniflorin, a novel heat-shock protein inducing compound, and human myometrial contractility in vitro

AIM

Heat shock proteins (HSPs) are synthesized in virtually all organisms in response to increases in temperature. They are associated with a relaxant effect on the human myometrium and are present in decreased concentration in the myometrium at the time of labor. Paeoniflorin is derived from Paeonia lactiflora and has been shown to induce the synthesis of HSPs in cultured mammalian cells. The purpose of the study was to evaluate the effect of paeoniflorin on human uterine contractility.

MATERIAL AND METHODS

Samples of human myometrium were taken at lower segment cesarean section. Dissected muscle strips were suspended under isometric conditions and exposed to cumulative additions of paeoniflorin in concentrations ranging from 1 nmol/L to 10 mol/L. Control experiments were simultaneously performed.

RESULTS

Paeoniflorin was found to exert an inhibitory effect on spontaneous and agonist-induced contractions compared to control strips. The mean maximal inhibition values were: 42.21% ± 9.26 for spontaneous contractions (n = 6; P < 0.0001) and 47.84% ± 9.05 for oxytocin-induced contractions (n = 6; P < 0.0001).

CONCLUSION

The HSP inducing compound, paeoniflorin, had a relaxant effect on human uterine contractility in vitro. These results reinforce the fact that HSPs may play a physiological role in the onset of labor and may also provide future targets for novel tocolytic treatments.

Paeoniflorin Protects against Nonalcoholic Fatty Liver Disease Induced by a High-Fat Diet in Mice

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. Paeoniflorin, a natural product and active ingredient of Paeonia lactiflora, has been demonstrated to have many pharmacological effects including antiinflammatory and antihyperglycemic activity. We investigated the effects of paeoniflorin on NAFLD in mice and its underlying mechanisms. We examined this hypothesis using a well-established animal model of NAFLD. The effects of paeoniflorin on inflammation and glucolipid metabolism disorder were evaluated. The corresponding signaling pathways were measured using real-time polymerase chain reaction (PCR). We demonstrated that the mice developed obesity, dyslipidemia, and fatty liver, which formed the NAFLD model. Paeoniflorin attenuated NAFLD and exhibited potential cardiovascular protective effects in vivo by lowering body weight, hyperlipidemia, and insulin resistance; blocking inflammation; and inhibiting lipid ectopic deposition. Further investigation revealed that the antagonistic effect on hyperlipidemia and lipid ectopic deposition was related to lowering the lipid synthesis pathway (de novo pathway, 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMG-CoAR)), promoting fatty acid oxidation [peroxisome proliferator-activated receptor-alpha (PPARα), carnitine palmitoyltransferase-1, etc.] and increasing cholesterol output (PPARγ-liver X receptor-α-ATP-binding cassette transporter-1); the inhibitory effects on inflammation and hyperglycemia were mediated by blocking inflammatory genes activation and reducing gluconeogenic genes expression (phosphoenolpyruvate carboxykinase and G6Pase). These results suggest that paeoniflorin prevents the development of NAFLD and reduces the risks of atherosclerosis through multiple intracellular signaling pathways. It may therefore be a potential therapeutic compound for NAFLD.

Post-stroke pain hypersensitivity induced by experimental thalamic hemorrhage in rats is region-specific and demonstrates limited efficacy of gabapentin

Intractable central post-stroke pain (CPSP) is one of the most common sequelae of stroke, but has been inadequately studied to date. In this study, we first determined the relationship between the lesion site and changes in mechanical or thermal pain sensitivity in a rat CPSP model with experimental thalamic hemorrhage produced by unilateral intra-thalamic collagenase IV (ITC) injection. Then, we evaluated the efficacy of gabapentin (GBP), an anticonvulsant that binds the voltage-gated Ca(2+) channel α2δ and a commonly used anti-neuropathic pain medication. Histological case-by-case analysis showed that only lesions confined to the medial lemniscus and the ventroposterior lateral/medial nuclei of the thalamus and/or the posterior thalamic nucleus resulted in bilateral mechanical pain hypersensitivity. All of the animals displaying CPSP also had impaired motor coordination, while control rats with intra-thalamic saline developed no central pain or motor deficits. GBP had a dose-related anti-allodynic effect after a single administration (1, 10, or 100 mg/kg) on day 7 post-ITC, with significant effects lasting at least 5 h for the higher doses. However, repeated treatment, once a day for two weeks, resulted in complete loss of effectiveness (drug tolerance) at 10 mg/kg, while effectiveness remained at 100 mg/kg, although the time period of efficacious analgesia was reduced. In addition, GBP did not change the basal pain sensitivity and the motor impairment caused by the ITC lesion, suggesting selective action of GBP on the somatosensory system.

Paeoniflorin of Paeonia lactiflora prevents renal interstitial fibrosis induced by unilateral ureteral obstruction in mice

Paeoniflorin (PF), the major active constituent of Paeonia lactiflora Pallas, has previously been reported to alleviate hepatic fibrosis. Whether and how it affects renal fibrosis was evaluated in the present study. The experimental renal fibrosis was induced by unilateral ureteral obstruction (UUO) operation in mice, and PF was orally administered for consecutive 7 days. Renal interstitial destruction and fibrosis degree were evaluated by histopathological examination and hydroxyproline assay. It was shown that PF treatment markedly ameliorated renal interstitial fibrotic lesions, attenuated synthesis of collagen and plasminogen activator inhibitor-1 (PAI-1), an important inhibitor of extracellular matrix degrading enzymes, in UUO mice. PF also suppressed epithelial-mesenchymal transition (EMT) by down-regulating TGF-β1 expression and maintaining BMP-7 mRNA expression, and inhibited Smad2/3 activation in fibrotic kidneys induced by UUO. These observations suggest that PF can effectively prevent renal interstitial fibrosis, and the underlying mechanisms are, at least in part, through blocking EMT via BMP-7 recovery and TGF-β/Smad signaling inhibition.

Efficacy of traditional Japanese herbal medicines-Keishikajutsubuto (TJ-18) and Bushi-matsu (TJ-3022)-against postherpetic neuralgia aggravated by self-reported cold stimulation: a case series

OBJECTIVES

It has been reported that postherpetic neuralgia (PHN) in patients over 60 years of age is aggravated under cold stimulation and is often difficult to treat. Keishikajutsubuto (TJ-18) and Bushi-matsu (TJ-3022) are traditional Japanese herbal medicines and have long been used to treat neuralgia and arthralgia, which are aggravated following cold stimulation. This study was designed to evaluate the effectiveness of combined TJ-18 and TJ-3022 therapy in cases of PHN aggravated by self-reported cold stimulation.

DESIGN

Fifteen (15) PHN patients aged 60 years and over were examined. Patients were aware of the persistent pain despite other treatments; pain was generally aggravated following exposure to cold stimulation. First, TJ-18 (7.5 g/day) was administered to patients, and then TJ-3022 (1.0 g/day) was also administered and progressively increased by 0.5-1.0 g increments every 2-4 weeks, until stable improvement was achieved, which was rated using the visual analogue scale (VAS). Analgesic effects were evaluated using the VAS during each patient visit.

OUTCOME MEASURES

Background variables, responses to treatment (time course of VAS rating, VAS improvement rate), the amount of additional TJ-3022 administered, and adverse reactions were analyzed.

RESULTS

Twelve (12) of the 15 patients completed the entire trial. Patient ages were 61-85 years, the male-to-female ratio was 4:8, and length of time after onset of herpes zoster was 2-92 months. In 3 patients, oral TJ-18 treatment was not possible due to hot flash or gastric discomfort. The VAS improvement rate for patients being orally administered both TJ-18 and TJ-3022 was 76.5±27.7% (mean±standard deviation). The additional TJ-3022 dose was 1.0-5.0 g/day. Twelve (12) patients have been treated without serious adverse reactions.

CONCLUSIONS

TJ-18 and TJ-3022 combination treatment is a promising means of treating intractable PHN, which has a self-reported tendency to aggravate pain under cold stimulation.

Paeoniflorin protects against lipopolysaccharide-induced acute lung injury in mice by alleviating inflammatory cell infiltration and microvascular permeability

OBJECTIVE

The present study aims to explore the effects of paeoniflorin (PF), a monoterpene glycoside isolated from the roots of Paeonia lactiflora Pallas, on acute lung injury (ALI) and the possible mechanisms.

MATERIALS AND METHOD

ALI was induced in mice by an intratracheal instillation of lipopolysaccharide (LPS, 1 mg/kg), and PF was injected intraperitoneally 30 min prior to LPS administration. After 24 h, lung water content, histology, microvascular permeability and proinflammatory cytokines in the bronchoaveolar lavage fluid were evaluated.

RESULTS

It was shown that PF (50, 100 mg/kg) could alleviate LPS-induced ALI, evidenced by reduced pulmonary edema, improved histological changes, and attenuated inflammatory cell accumulation in the interstitium and alveolar space as well as microvascular permeability. It also markedly down-regulated the expressions of proinflammatory cytokines interleukin (IL)-1β and tumor necrosis factor (TNF)-α at both transcription and protein levels. Additionally, PF inhibited the phosphorylations of p38 MAP kinase (p38) and c-Jun NH2-terminal kinase (JNK) but not extracellular signal-regulated kinase (ERK), and prevented the activation of nuclear factor-kappa B (NF-κB) in the lung tissues.

CONCLUSION

The findings suggest that PF is able to alleviate ALI, and the underlying mechanisms are probably attributed to decreasing the production of proinflammatory cytokines through down-regulation of the activation of p38, JNK and NF-κB pathways in lung tissues.

The nociceptive and anti-nociceptive effects of bee venom injection and therapy: a double-edged sword

Bee venom injection as a therapy, like many other complementary and alternative medicine approaches, has been used for thousands of years to attempt to alleviate a range of diseases including arthritis. More recently, additional theraupeutic goals have been added to the list of diseases making this a critical time to evaluate the evidence for the beneficial and adverse effects of bee venom injection. Although reports of pain reduction (analgesic and antinociceptive) and anti-inflammatory effects of bee venom injection are accumulating in the literature, it is common knowledge that bee venom stings are painful and produce inflammation. In addition, a significant number of studies have been performed in the past decade highlighting that injection of bee venom and components of bee venom produce significant signs of pain or nociception, inflammation and many effects at multiple levels of immediate, acute and prolonged pain processes. This report reviews the extensive new data regarding the deleterious effects of bee venom injection in people and animals, our current understanding of the responsible underlying mechanisms and critical venom components, and provides a critical evaluation of reports of the beneficial effects of bee venom injection in people and animals and the proposed underlying mechanisms. Although further studies are required to make firm conclusions, therapeutic bee venom injection may be beneficial for some patients, but may also be harmful. This report highlights key patterns of results, critical shortcomings, and essential areas requiring further study.

Imbalance between excitatory and inhibitory amino acids at spinal level is associated with maintenance of persistent pain-related behaviors

Although the postsynaptic events responsible for development of pathological pain have been intensively studied, the relative contribution of presynaptic neurotransmitters to the whole process remains less elucidated. In the present investigation, we sought to measure temporal changes in spinal release of both excitatory amino acids (EAAs, glutamate and aspartate) and inhibitory amino acids (IAAs, glycine, ?-aminobutyric acid and taurine) in response to peripheral inflammatory pain state. The results showed that following peripheral chemical insult induced by subcutaneous bee venom (BV) injection, there was an initial, parallel increase in spinal release of both EAAs and IAAs, however, the balance between them was gradually disrupted when pain persisted longer, with EAAs remaining at higher level but IAAs at a level below the baseline. Moreover, the EAAs-IAAs imbalance at the spinal level was dependent upon the ongoing activity from the peripheral injury site. Intrathecal blockade of ionotropic (NMDA and non-NMDA) and metabotropic (mGluRI, II, III) glutamate receptors, respectively, resulted in a differential inhibition of BV-induced different types of pain (persistent nociception vs. hyperalgesia, or thermal vs. mechanical hyperalgesia), implicating that spinal antagonism of any specific glutamate receptor subtype fails to block all types of pain-related behaviors. This result provides a new line of evidence emphasizing an importance of restoration of EAAs-IAAs balance at the spinal level to prevent persistence or chronicity of pain.

Endogenous opiates and behavior: 2007

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.