Anti-Hyperalgesic Efficacy of Acetyl L-Carnitine (ALCAR) Against Visceral Pain Induced by Colitis: Involvement of Glia in the Enteric and Central Nervous System.

The management of abdominal pain in patients affected by inflammatory bowel diseases (IBDs) still represents a problem because of the lack of effective treatments. Acetyl L-carnitine (ALCAR) has proved useful in the treatment of different types of chronic pain with excellent tolerability. The present work aimed at evaluating the anti-hyperalgesic efficacy of ALCAR in a model of persistent visceral pain associated with colitis induced by 2,4-dinitrobenzene sulfonic acid (DNBS) injection. Two different protocols were applied. In the preventive protocol, ALCAR was administered daily starting 14 days to 24 h before the delivery of DNBS. In the interventive protocol, ALCAR was daily administered starting the same day of DNBS injection, and the treatment was continued for 14 days. In both cases, ALCAR significantly reduced the establishment of visceral hyperalgesia in DNBS-treated animals, though the interventive protocol showed a greater efficacy than the preventive one. The interventive protocol partially reduced colon damage in rats, counteracting enteric glia and spinal astrocyte activation resulting from colitis, as analyzed by immunofluorescence. On the other hand, the preventive protocol effectively protected enteric neurons from the inflammatory insult. These findings suggest the putative usefulness of ALCAR as a food supplement for patients suffering from IBDs.

Ellagitannins and triterpenoids extracts of Anogeissus leiocarpus stem bark extracts: Protective effects against osteoarthritis.

Osteoarthritis (OA) is a complex joint disease characterized by persistent pain. Unfortunately, current pharmacological therapies are unsatisfactory and characterized by side effects, reason why new strategies are needed. We tested the efficacy of different classes of compounds, ellagitannins and olean-type triterpenoids, contained in Anogeissus leiocarpus extract (Combretaceae family) in comparison to ellagitannins of Castanea sativa extract in a rat model of osteoarthritis induced by the intra-articular injection of sodium monoiodoacetate (MIA). The decoction of stem bark of A. leiocarpus AL-DEC-TOT (300 mg/kg; 4.8% triterpenoids; 11.0% tannins), the butanol extract AL-BuOH-EXT (120 mg/kg; triterpenoids 20.9%; tannins 6.4%) and its correlated aqueous residue AL-Res-H2 O (300 mg/kg; triterpenoids 0.7%; tannins 8.7%) and the decoction of C. sativa, CS-DEC-TOT, (240 mg/kg; triterpenoids 0.65%; tannins 10.8%) were orally administered for two weeks starting from the day of the damage. Behavioural tests highlighted that all stem bark extracts of A. leiocarpus counteracted hypersensitivity development, reduced spontaneous pain, and improved motor skills. Histologically, AL-DEC-TOT, AL-BuOH-EXT and AL-Res-H2 O were effective in preventing joint alterations. In conclusion, all the extracts were effective demonstrating that both olean-type triterpenoid and ellagitannin fractions have anti-hypersensitivity and restorative properties running the stem bark extracts of A. leiocarpus as a candidate in the treatment of OA.

Echinacea purpurea against neuropathic pain: Alkamides versus polyphenols efficacy.

Chemotherapy-induced neuropathy represents the main dose-limiting toxicity of several anticancer drugs, such as oxaliplatin, leading to chronic pain and an impairment of the quality of life. Echinacea purpurea n-hexane extract (EP4 -RE ; rich in alkamides) and butanolic extract (EP4 -RBU ; rich in polyphenols) have been characterized and tested in an in vivo model of oxaliplatin-induced neuropathic pain, addressing the endocannabinoid system with alkamides and counteracting the redox imbalance with polyphenols. Thermal hypersensitivity was evaluated by the Cold Plate test. EP4 -RE showed a dose-dependent anti-hyperalgesic profile. The extract was more effective than its main constituent, dodeca-2 E,4 E,8Z,10 E/Z-tetraenoic acid isobutylamide (18 mg kg-1 , twofold to equimolar EP4 -RE 30 mg kg-1 ), suggesting a synergy with other extract constituents. Administration of cannabinoid type 2 (CB2) receptor-selective antagonist completely blocked the anti-allodynic effect of EP4 -RE , differently from the antagonism of CB1 receptors. EP4 -RBU (30 mg kg-1 ) exhibited anti-neuropathic properties too. The effect was mainly exerted by chicoric acid, which administered alone (123 µg kg-1 , equimolar to EP4 -RBU 30 mg kg-1 ) completely reverted oxaliplatin-induced allodynia. A synergy between different polyphenols in the extract had not been highlighted. Echinacea extracts have therapeutic potential in the treatment of neuropathic pain, through both alkamides CB2-selective activity and polyphenols protective properties.

Beneficial Effect of H2S-Releasing Molecules in an In Vitro Model of Sarcopenia: Relevance of Glucoraphanin.

Sarcopenia is a gradual and generalized skeletal muscle (SKM) syndrome, characterized by the impairment of muscle components and functionality. Hydrogen sulfide (H2S), endogenously formed within the body from the activity of cystathionine-γ-lyase (CSE), cystathionine- ß-synthase (CBS), and mercaptopyruvate sulfurtransferase, is involved in SKM function. Here, in an in vitro model of sarcopenia based on damage induced by dexamethasone (DEX, 1 µM, 48 h treatment) in C2C12-derived myotubes, we investigated the protective potential of exogenous and endogenous sources of H2S, i.e., glucoraphanin (30 µM), L-cysteine (150 µM), and 3-mercaptopyruvate (150 µM). DEX impaired the H2S signalling in terms of a reduction in CBS and CSE expression and H2S biosynthesis. Glucoraphanin and 3-mercaptopyruvate but not L-cysteine prevented the apoptotic process induced by DEX. In parallel, the H2S-releasing molecules reduced the oxidative unbalance evoked by DEX, reducing catalase activity, O2- levels, and protein carbonylation. Glucoraphanin, 3-mercaptopyruvate, and L-cysteine avoided the changes in myotubes morphology and morphometrics after DEX treatment. In conclusion, in an in vitro model of sarcopenia, an impairment in CBS/CSE/H2S signalling occurs, whereas glucoraphanin, a natural H2S-releasing molecule, appears more effective for preventing the SKM damage. Therefore, glucoraphanin supplementation could be an innovative therapeutic approach in the management of sarcopenia.

Determination of Folic Acid Using Biosensors-A Short Review of Recent Progress.

Folic acid (FA) is the synthetic surrogate of the essential B vitamin folate, alternatively named folacin, pteroylglutamic acid or vitamin B9. FA is an electroactive compound that helps our body to create and keep our cells healthy: it acts as the main character in a variety of synthetic biological reactions such as the synthesis of purines, pyrimidine (thus being indirectly implied in DNA synthesis), fixing and methylation of DNA. Therefore, physiological folate deficiency may be responsible for severe degenerative conditions, including neural tube defects in developing embryos and megaloblastic anaemia at any age. Moreover, being a water-soluble molecule, it is constantly lost and has to be reintegrated daily; for this reason, FA supplements and food fortification are, nowadays, extremely diffused and well-established practices. Consequently, accurate, reliable and precise analytical techniques are needed to exactly determine FA concentration in various media. Thus, the aim of this review is to report on research papers of the past 5 years (2016-2020) dealing with rapid and low-cost electrochemical determination of FA in food or biological fluid samples.

Comparative Assessment of the Activity of Racemic and Dextrorotatory Forms of Thioctic (Alpha-Lipoic) Acid in Low Back Pain: Preclinical Results and Clinical Evidences From an Open Randomized Trial.

Peripheral neuropathies, characterized by altered nociceptive and muscular functions, are related to oxidative stress. Thioctic acid is a natural antioxidant existing as two optical isomers, but most clinically used as racemic mixture. The present study investigated the central nervous system's changes which followed loose-ligation-derived compression of sciatic nerve, the putative neuroprotective role of thioctic acid and the pain-alleviating effect on low-back pain suffering patients. Loose ligation of the right sciatic nerve was performed in spontaneously hypertensive rats (SHR), a model of increased oxidative stress, and in normotensive Wistar-Kyoto rats (WKY). Animals with sciatic nerve ligation were left untreated or were treated intraperitoneally for 15 days with 250 µmol·kg-1·die-1 of (+/-)-thioctic acid; 125 µmol·kg-1·die-1 of (+/-)-thioctic acid; 125 µmol·kg-1·die-1 of (+)-thioctic acid lysine salt; 125 µmol·kg-1·die-1 of (-)-thioctic acid; 300 µmol·kg-1·die-1 pregabalin. Control SHR and WKY rats received the same amounts of vehicle. The clinical trial NESTIORADE (Sensory-Motor Neuropathies of the Sciatic Nerve: Comparative evaluation of the effect of racemic and dextro-rotatory forms of thioctic acid) examined 100 patients (49 males and 51 females aged 53 ± 11 years) dividing them into two equal-numbered groups, each treated daily for 60 days with 600 mg of (+/-)-thioctic acid or (+)-thioctic acid, respectively. The trial was registered prior to patient enrollment at EudraCT website (OSSC Number: 2011-000964-81). In the preclinical study, (+)-thioctic acid was more active than (+/-)- or (-)-enantiomers in relieving pain and protecting peripheral nerve as well as in reducing oxidative stress and astrogliosis in the spinal cord. Main findings of NESTIORADE clinical trial showed a greater influence on painful symptomatology, a quicker recovery and a better impact on quality of life of (+)-thioctic acid vs. (+/-)-thioctic acid. These data may have a pharmacological and pharmacoeconomical relevance and suggest that thioctic acid, above all (+)-enantiomer, could be considered for treatment of low-back pain involving neuropathy.

Efficacy of Posidonia oceanica Extract against Inflammatory Pain: In Vivo Studies in Mice.

Posidonia oceanica (L.) Delile is traditionally used for its beneficial properties. Recently, promising antioxidant and anti-inflammatory biological properties emerged through studying the in vitro activity of the ethanolic leaves extract (POE). The present study aims to investigate the anti-inflammatory and analgesic role of POE in mice. Inflammatory pain was modeled in CD-1 mice by the intraplantar injection of carrageenan, interleukin IL-1ß and formalin. Pain threshold was measured by von Frey and paw pressure tests. Nociceptive pain was studied by the hot-plate test. POE (10-100 mg kg-1) was administered per os. The paw soft tissue of carrageenan-treated animals was analyzed to measure anti-inflammatory and antioxidant effects. POE exerted a dose-dependent, acute anti-inflammatory effect able to counteract carrageenan-induced pain and paw oedema. Similar anti-hyperalgesic and anti-allodynic results were obtained when inflammation was induced by IL-1ß. In the formalin test, the pre-treatment with POE significantly reduced the nocifensive behavior. Moreover, POE was able to evoke an analgesic effect in naïve animals. Ex vivo, POE reduced the myeloperoxidase activity as well as TNF-α and IL-1ß levels; further antioxidant properties were highlighted as a reduction in NO concentration. POE is the candidate for a new valid strategy against inflammation and pain.

Extra virgin olive oil and related by-products (Olea europaea L.) as natural sources of phenolic compounds for abdominal pain relief in gastrointestinal disorders in rats.

Management of abdominal pain, a common symptom of IBDs and IBS, is still a clinical problem. Extra virgin olive oil (EVOO), a main component of the Mediterranean diet, shows positive effects on chronic inflammation in IBDs. In this study, the effect of the oral administration of EVOO (3 mL) and two olive milling by-products, DPA (300 mg kg-1) and DRF (300 mg kg-1), on preventing the development of abdominal pain in a DNBS-induced colitis model in rats was evaluated. The doses were chosen with the aim of simulating a plausible daily intake in humans. DPA and EVOO treatments significantly reduced the abdominal viscero-motor response to colon-rectal distension at 2 and 3 mL of balloon distension volume, both 7 and 14 days after the DNBS-injection. DRF showed efficacy in the reduction of visceral hypersensitivity only with 3 mL balloon inflation. In awake animals, DPA and DRF reduced pain perception (evaluated as abdominal withdrawal reflex) with all balloon distension volumes, while EVOO was effective only with higher distension volumes. Fourteen days after the DNBS-injection, all samples reduced the macroscopic intestinal damage (quantified as the macroscopic damage score) also showing, at the microscopic level, a reduction of the inflammatory infiltrate (quantified by hematoxylin and eosin analysis), fibrosis (highlighted by picrosirius red staining), the increase in mast cells and their degranulation (analyzed by triptase immunohistochemistry). This is the first report on the promotion of abdominal pain relief in a rat model obtained administering EVOO and two derived by-products. Our results suggest a protective role of phenol-rich EVOO and milling by-products, which may be proposed as food ingredients for novel functional foods.

Pomegranate Mesocarp against Colitis-Induced Visceral Pain in Rats: Effects of a Decoction and Its Fractions.

The management of chronic visceral pain related to Inflammatory Bowel Diseases or Irritable Bowel Syndrome is still a clinical problem and new therapeutic strategies continue to be investigated. In the present study, the efficacy of a pomegranate decoction and of its polysaccharide and ellagitannin components in preventing the development of colitis-induced abdominal pain in rats was evaluated. After colitis induction by 2,4-dinitrobenzenesulfonic acid (DNBS), the pomegranate decoction (300 mg kg-1), polysaccharides (300 mg kg-1), and ellagitannins (45 mg kg-1) were orally administered for 14 days. Repeated treatment with decoction reduced visceral hypersensitivity in the colitic animals both at 7 and 14 days. Similar efficacy was shown by polysaccharides, but with lower potency. Ellagitannins administered at dose equivalent to decoction content showed higher efficacy in reducing the development of visceral pain. Macroscopic and microscopic evaluations performed on the colon 14 days after the damage showed that all three preparations reduced the overall amount of mast cells, the number of degranulated mast cells, and the density of collagen fibers in the mucosal stroma. Although ellagitannins seem to be responsible for most of the beneficial effects of pomegranate on DNBS-induced colitis, the polysaccharides support and enhance its effect. Therefore, pomegranate mesocarp preparations could represent a complementary approach to conventional therapies for promoting abdominal pain relief.

The Use of the Selective Imidazoline I1 Receptor Agonist Carbophenyline as a Strategy for Neuropathic Pain Relief: Preclinical Evaluation in a Mouse Model of Oxaliplatin-Induced Neurotoxicity.

Anti-cancer therapy based on the repeated administration of oxaliplatin is limited by the development of a disabling neuropathic syndrome with detrimental effects on the patient's quality of life. The lack of effective pharmacological approaches calls for the identification of innovative therapeutic strategies based on new targets. We focused our attention on the imidazoline I1 receptor (I1-R) and in particular on the selective I1-R agonist 2-(1-([1,1'-biphenyl]-2-yl)propan-2-yl)-4,5-dihydro-1H-imidazole) (carbophenyline). The purpose of this work was the preclinical evaluation of the efficacy of carbophenyline on oxaliplatin-induced neuropathic pain in mice. Carbophenyline, acutely per os administered (0.1-10 mg kg-1), induced a dose-dependent anti-hyperalgesic effect that was completely blocked by the pre-treatment with the I1-R antagonist 3 or the I1/α2 receptor antagonist efaroxan, confirming the I1-R-dependent mechanism. Conversely, pre-treatment with the I2-R antagonist BU224 did not block the anti-nociceptive effect evoked by carbophenyline. Repeated oral administrations of carbophenyline (1 mg kg-1) for 14 days, starting from the first day of oxaliplatin injection, counteracted the development of neuropathic pain in all behavioral tests (cold plate, Von Frey, and paw pressure tests) carried out 24 h after the last carbophenyline treatment on days 7 and 14. In the dorsal horn of the spinal cord, carbophenyline significantly decreased the oxaliplatin-induced astrocyte activation detected by immunofluorescence staining by the specific labelling with GFAP antibody. In conclusion, carbophenyline showed anti-neuropathic properties both after acute and chronic treatment with preventive effect against oxaliplatin-induced astrocyte activation in the spinal cord. Therefore, I1-R agonists emerge as a new class of candidates for the management of oxaliplatin-induced neuropathic pain.

Treatment of Non-Alcoholic Steatosis: Preclinical Study of a New Nutraceutical Multitarget Formulation.

Multifactorial pathogenesis of non-alcoholic steatohepatitis (NASH) disease, a wide-spread liver pathology associated with metabolic alterations triggered by hepatic steatosis, should be hit by multitarget therapeutics. We tested a multicomponent food supplement mixture (AP-NHm), whose components have anti-dislipidemic, antioxidant and anti-inflammatory effects, on in vitro and in vivo models of NASH. In vitro, hepatic cells cultures were treated for 24 h with 0.5 mM oleic acid (OA): in the co-treatment set cells were co-treated with AP-NH mixtures (AP-NHm, 1:3:10 ratio) and in the post-injury set AP-NHm was added for 48 h after OA damage. In vivo, C57BL/6 mice were fed with high-fat diet (HFD) for 12 weeks, inducing NASH at 7th week, and treated with AP-NHm at two dosages (1:3 ratio) in co-treatment or post-injury protocols, while a control group was fed with a standard diet. In in vitro co-treatment protocol, alterations of redox balance, proinflammatory cytokines release and glucose uptake were restored in a dose-dependent manner, at highest dosages also in post-injury regimen. In both regimens, pathologic dyslipidemias were also ameliorated by AP-NHm. In vivo, high-dose-AP-NHm-co-treated-HFD mice dose-dependently gained less body weight, were protected from dyslipidemia, and showed a lower liver weight. Dose-dependently, AP-NHm treatment lowered hepatic LDL, HDL, triglycerides levels and oxidative damage; co-treatment regimen was anti-inflammatory, reducing TNF-α and IL-8 levels. Hepatic lipidic infiltration significantly decreased in co-treated and post-injury-AP-NHm-HFD animals. The multitarget approach with AP-NHm was effective in preventing and reducing NASH-related pathologic features, warranting for the clinical development of this compound.

Intra-Articular Route for the System of Molecules 14G1862 from Centella Asiatica: Pain Relieving and Protective Effects in a Rat Model of Osteoarthritis.

Current pharmacological therapies for the management of chronic articular diseases are far from being satisfactory, so new strategies need to be investigated. We tested the intra-articular pain relieving properties of a system of molecules from a characterized Centella asiatica extract (14G1862) in a rat model of osteoarthritis induced by monoiodoacetate (MIA). 14G1862 (0.2-2 mg mL-1) was intra-articularly (i.a.) injected 7 days after MIA, behavioural and histological evaluations were performed 14, 30 and 60 days after treatments. Moreover, the effect of 14G1862 on nitrate production and iNOS expression in RAW 264.7 macrophages stimulated with LPS was assessed. In vitro, 14G1862 treatment attenuated LPS-induced NO production and iNOS expression in a comparable manner to celecoxib. In vivo, 14G1862 significantly reduced mechanical allodynia and hyperalgesia, spontaneous pain and motor alterations starting on day 14 up to day 60. The efficacy was higher or comparable to that evoked by triamcinolone acetonide (100 µg i.a.) used as reference drug. Histological evaluation highlighted the improvement of several morphological parameters in MIA + 14G1862-treated animals with particularly benefic effects on joint space and fibrin deposition. In conclusion, i.a. treatment with Centella asiatica is a candidate to be a novel effective approach for osteoarthritis therapy.

Bacopa monnieri as augmentation therapy in the treatment of anhedonia, preclinical and clinical evaluation.

Bacopa monnieri (L.) is widely used in Ayurvedic medicine as a neural tonic for improving intelligence and memory. Several studies highlighted its efficacy in neuropsychiatric diseases but there is no evidence regarding anhedonia. Aim of the present work was to preclinically and clinically test against anhedonia a standardized B. monnieri extract (20% bacosides). In a mouse model of a depressive-like syndrome induced by lipopolysaccharide (LPS), the daily administration of the extract (50-200 mg kg-1 , p.o.) for 1 week, dose-dependently counteracted the immobility time in Porsolt and Tail suspension tests (p < .01). At the sucrose preference test (directly related to the ability for feeling pleasure) the extract treatment (100 and 200 mg kg-1 ) counteracted the reduction of sucrose intake induced by LPS (p < .01). Moreover, B. monnieri significantly reduced cytokines, cortisol, and artemin LPS-dependent alterations in plasma while increased the brain-derived neurotrophic factor levels (p < .05). The efficacy of the same extract was tested in a clinical study in which 42 patients with significant degree of anhedonia (evaluated as Snaith-Hamilton Pleasure Scale [SHAPS] score ≥ 3) were enrolled. Patients were divided into two groups and treated with citalopram or citalopram associated with B. monnieri (300 mg bid) for 4 weeks. The Pears Sample T-test showed a significant improvement (p < .05) in relevant scales (Hamilton depression rating scale, SHAPS, and strength and difficulties questionnaire) in the extract-treated group in comparison to citalopram alone was recorded. These data suggest that B. monnieri extract may be effective for the management of anhedonia and therefore should be considered for future controlled trials.

Researching New Therapeutic Approaches for Abdominal Visceral Pain Treatment: Preclinical Effects of an Assembled System of Molecules of Vegetal Origin.

Abdominal pain is a frequent symptom of irritable bowel syndrome (IBS) and inflammatory bowel diseases (IBDs). Although the knowledge of these pathologies is progressing, new therapeutic strategies continue to be investigated. In the present study, the effect of a system of molecules of natural origin (a medical device according to EU Directive 93/42/EC, engineered starting from Boswellia serrata resins, Aloe vera polysaccharides and Matricaria chamomilla and Melissa officinalis polyphenols) was evaluated against the intestinal damage and visceral pain development in DNBS-induced colitis model in rats. The system (250 and 500 mg kg-1) was orally administered once daily, starting three days before the injection of 2,4-dinitrobenzenesulfonic acid (DNBS) and for 14 days thereafter. The viscero-motor response (VMR) to colon-rectal balloon distension (CRD) was used as measure of visceral sensitivity. The product significantly reduced the VMR of DNBS-treated animals. Its effect on pain threshold was better than dexamethasone and mesalazine, and not lower than amitriptyline and otilonium bromide. At microscopic and macroscopic level, the tested system was more effective in protecting the intestinal mucosa than dexamethasone and mesalazine, promoting the healing of tissue lesions. Therefore, we suggest that the described system of molecules of natural origin may represent a therapeutic option to manage painful bowel diseases.

Phaseolus vulgaris L. Extract: Alpha-Amylase Inhibition against Metabolic Syndrome in Mice.

To examine the effects of the alpha-amylase inhibitor isoform 1 called phaseolamin, a standardized extract from white kidney beans (Phaseolus vulgaris L) was tested against the hallmarks of metabolic syndrome. The efficacy of a per os repeated treatment with P. vulgaris extract (500 mg/kg) was compared with metformin (100 mg/kg) and atorvastatin (10 mg/kg) in a model of metabolic syndrome evoked by prolonged high fat diet (HFD; week 1 to week 19) in C57BL/6 mice. Bean extract and compounds administration started after metabolic syndrome establishment (week 11). P. vulgaris extract reduced the body weight overtime, as well as effectively lowered glycaemia, triglycerides, and cholesterol. On week 19, bean extract normalized the HFD-evoked tolerance to glucose and insulin. According to the phytochemical characterization, it inhibited the alpha-amylase activity. Animals treated with the extract were rescued from motor impairments and nociceptive threshold alterations induced by HFD. Specific organs analysis revealed that P. vulgaris extract decreased hepatic steatosis and lipid peroxidation in liver. It protected the heart from HFD oxidative alterations increasing the expression of the detoxifying enzymes catalase and glutathione reductase, and normalizing NADH dehydrogenase level. The histological analysis of aorta showed a protection about the development of fatty streaks in the muscular layers. In conclusion, a prolonged treatment with the standardized extract of P. vulgaris significantly reduced several pathological features related to a metabolic syndrome-like condition; a multifactorial approach that candidates this vegetal product as a possible therapeutic option against metabolic syndrome.

Effect of NIR laser therapy by MLS-MiS source against neuropathic pain in rats: in vivo and ex vivo analysis.

Neuropathic pain is characterized by an uncertain etiology and by a poor response to common therapies. The ineffectiveness and the frequent side effects of the drugs used to counteract neuropathic pain call for the discovery of new therapeutic strategies. Laser therapy proved to be effective for reducing pain sensitivity thus improving the quality of life. However, its application parameters and efficacy in chronic pain must be further analyzed. We investigated the pain relieving and protective effect of Photobiomodulation Therapy in a rat model of compressive mononeuropathy induced by Chronic Constriction Injury of the sciatic nerve (CCI). Laser (MLS-MiS) applications started 7 days after surgery and were performed ten times over a three week period showing a reduction in mechanical hypersensitivity and spontaneous pain that started from the first laser treatment until the end of the experiment. The ex vivo analysis highlighted the protective role of laser through the myelin sheath recovery in the sciatic nerve, inhibition of iNOS expression and enhancement of EAAT-2 levels in the spinal cord. In conclusion, this study supports laser treatment as a future therapeutic strategy in patients suffering from neuropathic pain induced by trauma.

Intra-articular mucilages: behavioural and histological evaluations for a new model of articular pain.

OBJECTIVES: The creation of a new valid preclinical model of articular pain by the intra-articular (i.a.) injection of mucilages for the screening of new treatments against arthritis. METHODS: A single intra-articular injection (20 µl) of mucilages (from Althaea officinalis roots and Linum usitatissimun seeds) or vegetal components (Amorphophallus konjac gum powder and ß-glucan, used as reference standard) were assessed in the rat. The pathology progression was monitored by behavioural measurements (paw pressure test, von Frey test, incapacitance test and beam balance test) and compared to that induced by the i.a. injections of monoiodioacetate (MIA) and Complete Freund's Adjuvant (CFA), well-recognized models of osteoarthritis and rheumatoid arthritis, respectively. KEY FINDINGS: Among all, the mucilage of L. usitatissimun showed the best pro-algic profile inducing a painful long-lasting condition. Hypersensitivity was characterized as a mixed form of inflammatory and neuropathic pain by the responsiveness to ibuprofen (100 mg/kg, p.o.) and pregabalin (30 mg/kg, p.o.). The histological evaluation of joint showed a damage that represents both MIA and CFA features. CONCLUSIONS: In conclusion, a single i.a. injection of L. usitatissimun mucilage can represent a valid model to assess articular pain in the rat for the screening of new treatments against arthritis.

Effect of Vitis vinifera hydroalcoholic extract against oxaliplatin neurotoxicity: in vitro and in vivo evidence.

Oxaliplatin treatment is associated with the development of a dose-limiting painful neuropathy impairing patient's quality of life. Since oxidative unbalance is a relevant mechanism of oxaliplatin neurotoxicity, we assessed the potential antioxidant properties of Vitis vinifera extract in reducing oxaliplatin-induced neuropathy as a valuable therapeutic opportunity. A hydroalcoholic extract of Vitis vinifera red leaf was characterized and tested in primary rat astrocyte cells treated with oxaliplatin (100 µM). Oxaliplatin lethality in the human adenocarcinoma cell line HT-29 was evaluated in the absence and presence of the extract. In vivo, pain hypersensitivity was measured in a rat model of neuropathy induced by oxaliplatin and ex vivo molecular targets of redox balance were studied. Vitis vinifera extract (50 µg mL-1, 4 h incubation) significantly reduced the oxaliplatin-dependent superoxide anion increase and lipid peroxidation in rat astrocytes but did not interfere with the mortality elicited by oxaliplatin in HT-29 cancer cells. In oxaliplatin-treated rats, a repeated daily administration of the Vitis vinifera extract (300 mg kg-1, p.o.) significantly prevented mechanical and thermal hypersensitivity to noxious and non noxious stimuli. mRNA and protein levels of Nrf2 were normalized in spinal cord and DRGs. Moreover, in the spinal cord, the extract significantly decreased the activation of astrocytes. Vitis vinifera reduced oxidative damages and relieved pain without influencing oxaliplatin anti-cancer activity.

Effect of glucoraphanin and sulforaphane against chemotherapy-induced neuropathic pain: Kv7 potassium channels modulation by H2 S release in vivo.

The beneficial effects of isothiocyanate-based compounds, as well as their safety, have been shown in neuropathological disorders, such as neuropathic pain. Aim of the present work was to study the efficacy of the glucosinolate glucoraphanin (GRA) and the derived isothiocyanate sulforaphane (SFN), secondary metabolites occurring exclusively in Brassicales, on chemotherapy-induced neuropathic pain. Mice were repeatedly treated with oxaliplatin (2.4 mg kg-1 ip) for 14 days to induce neuropathic pain. GRA and SFN effects were evaluated after a single administration on Day 15 or after a daily repeated oral and subcutaneous treatment starting from the first day of oxaliplatin injection until the 14th day. Single subcutaneous and oral administrations of GRA (4.43-119.79 µmol kg-1 ) or SFN (1.33-13.31 µmol kg-1 ) reduced neuropathic pain in a dose-dependent manner. The repeated administration of GRA and SFN (respectively 13.31 and 4.43 µmol kg-1 ) prevented the chemotherapy-induced neuropathy. The co-administration of GRA and SFN in mixture with the H2 S binding molecule, haemoglobin, abolished their pain-relieving effect, which was also reverted by pretreating the animals with the selective blocker of Kv7 potassium channels, XE991. GRA and SFN reduce neuropathic pain by releasing H2 S and modulating Kv7 channels and show a protective effect on the chemotherapy-induced neuropathy.

Pain relieving and protective effects of Astragalus hydroalcoholic extract in rat arthritis models.

OBJECTIVES: The evaluation of the pharmacological profile of the dried 50% hydroalcoholic extract (50%HA) of Astragali radix in two different animal models of articular damage resembling osteoarthritis and rheumatoid arthritis. METHODS: Sodium monoiodoacetate (MIA) or complete Freund's adjuvant (CFA) was intra-articular injected (day 0) in the rat tibiotarsal joint to induce damages mimicking osteoarthritis or rheumatoid arthritis. Pain measurements (responses to non-noxious and noxious stimuli, spontaneous pain, articular pain) were assessed on days 7 and 14. On day 14, the tibiotarsal joints were explanted in order to measure the diameter and to assess histological evaluations. Furthermore, the plasmatic concentrations of inflammatory and anti-inflammatory cytokines were measured. KEY FINDINGS: A single administration of 50%HA (300 mg/kg per os) significantly reduced both MIA-induced pain and CFA-induced pain (78% and 96% pain relief, respectively). The repeated administration prevented the development of hypersensitivity on day 14. The haematoxylin/eosin staining revealed that 50% HA attenuated joint alterations in MIA-injected rats, and furthermore, the joint inflammatory infiltrate was reduced in both models (by about 50%). In CFA-treated rats, 50%HA lowered the plasmatic levels of the pro-inflammatory cytokines interleukin-1ß and tumour necrosis factor-α as well as the joint diameter. CONCLUSIONS: The 50% hydroalcoholic extract of Astragali radix is a valuable candidate for the adjuvant treatment of articular diseases.