Topical diosmetin attenuates nociception and inflammation in a ultraviolet B radiation-induced sunburn model in mice.

Burns are a global health problem and can be caused by several factors, including ultraviolet (UV) radiation. Exposure to UVB radiation can cause sunburn and a consequent inflammatory response characterised by pain, oedema, inflammatory cell infiltration, and erythema. Pharmacological treatments available to treat burns and the pain caused by them include nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, antimicrobials and glucocorticoids, which are associated with adverse effects. Therefore, the search for new therapeutic alternatives is needed. Diosmetin, an aglycone of the flavonoid diosmin, has antinociceptive, antioxidant and anti-inflammatory properties. Thus, we evaluated the antinociceptive and anti-inflammatory effects of topical diosmetin (0.01, 0.1 and 1%) in a UVB radiation-induced sunburn model in mice. The right hind paw of the anaesthetised mice was exposed only once to UVB radiation (0.75 J/cm2) and immediately treated with diosmetin once a day for 5 days. The diosmetin antinociceptive effect was evaluated by mechanical allodynia and pain affective-motivational behaviour, while its anti-inflammatory activity was assessed by measuring paw oedema and polymorphonuclear cell infiltration. Mice exposed to UVB radiation presented mechanical allodynia, increased pain affective-motivational behaviour, paw oedema and polymorphonuclear cell infiltration into the paw tissue. Topical Pemulen® TR2 1% diosmetin reduced the mechanical allodynia, the pain affective-motivational behaviour, the paw oedema and the number of polymorphonuclear cells in the mice's paw tissue similar to that presented by Pemulen® TR2 0.1% dexamethasone. These findings indicate that diosmetin has therapeutic potential and may be a promising strategy for treating patients experiencing inflammatory pain, especially those associated with sunburn.

Kinin B1 and B2 Receptors Contribute to Cisplatin-Induced Painful Peripheral Neuropathy in Male Mice.

Cisplatin is the preferential chemotherapeutic drug for highly prevalent solid tumours. However, its clinical efficacy is frequently limited due to neurotoxic effects such as peripheral neuropathy. Chemotherapy-induced peripheral neuropathy is a dose-dependent adverse condition that negatively impacts quality of life, and it may determine dosage limitations or even cancer treatment cessation. Thus, it is urgently necessary to identify pathophysiological mechanisms underlying these painful symptoms. As kinins and their B1 and B2 receptors contribute to the development of chronic painful conditions, including those induced by chemotherapy, the contribution of these receptors to cisplatin-induced peripheral neuropathy was evaluated via pharmacological antagonism and genetic manipulation in male Swiss mice. Cisplatin causes painful symptoms and impaired working and spatial memory. Kinin B1 (DALBK) and B2 (Icatibant) receptor antagonists attenuated some painful parameters. Local administration of kinin B1 and B2 receptor agonists (in sub-nociceptive doses) intensified the cisplatin-induced mechanical nociception attenuated by DALBK and Icatibant, respectively. In addition, antisense oligonucleotides to kinin B1 and B2 receptors reduced cisplatin-induced mechanical allodynia. Thus, kinin B1 and B2 receptors appear to be potential targets for the treatment of cisplatin-induced painful symptoms and may improve patients' adherence to treatment and their quality of life.

Kinin B1 and B2 receptors mediate cancer pain associated with both the tumor and oncology therapy using aromatase inhibitors.

Pain caused by the tumor or aromatase inhibitors (AIs) is a disabling symptom in breast cancer survivors. Their mechanisms are unclear, but pro-algesic and inflammatory mediators seem to be involved. Kinins are endogenous algogenic mediators associated with various painful conditions via B1 and B2 receptor activation, including chemotherapy-induced pain and breast cancer proliferation. We investigate the involvement of the kinin B1 and B2 receptors in metastatic breast tumor (4T1 breast cancer cells)-caused pain and in aromatase inhibitors (anastrozole or letrozole) therapy-associated pain. A protocol associating the tumor and antineoplastic therapy was also performed. Kinin receptors' role was investigated via pharmacological antagonism, receptors protein expression, and kinin levels. Mechanical and cold allodynia and muscle strength were evaluated. AIs and breast tumor increased kinin receptors expression, and tumor also increased kinin levels. AIs caused mechanical allodynia and reduced the muscle strength of mice. Kinin B1 (DALBk) and B2 (Icatibant) receptor antagonists attenuated these effects and reduced breast tumor-induced mechanical and cold allodynia. AIs or paclitaxel enhanced breast tumor-induced mechanical hypersensitivity, while DALBk and Icatibant prevented this increase. Antagonists did not interfere with paclitaxel's cytotoxic action in vitro. Thus, kinin B1 or B2 receptors can be a potential target for treating the pain caused by metastatic breast tumor and their antineoplastic therapy.

Kinins and their B1 and B2 receptors as potential therapeutic targets for pain relief.

Kinins are endogenous peptides that belong to the kallikrein-kinin system, which has been extensively studied for over a century. Their essential role in multiple physiological and pathological processes is demonstrated by activating two transmembrane G-protein-coupled receptors, the kinin B1 and B2 receptors. The attention is mainly given to the pathological role of kinins in pain transduction mechanisms. In the past years, a wide range of preclinical studies has amounted to the literature reinforcing the need for an updated review about the participation of kinins and their receptors in pain disorders. Here, we performed an extensive literature search since 2004, describing the historical progress and the current understanding of the kinin receptors' participation and its potential therapeutic in several acute and chronic painful conditions. These include inflammatory (mainly arthritis), neuropathic (caused by different aetiologies, such as cancer, multiple sclerosis, antineoplastic toxicity and diabetes) and nociplastic (mainly fibromyalgia) pain. Moreover, we highlighted the pharmacological actions and possible clinical applications of the kinin B1 and B2 receptor antagonists, kallikrein inhibitors or kallikrein-kinin system signalling pathways-target molecules in these different painful conditions. Notably, recent findings sought to elucidate mechanisms for guiding new and better drug design targeting kinin B1 and B2 receptors to treat a disease diversity. Since the kinin B2 receptor antagonist, Icatibant, is clinically used and well-tolerated by patients with hereditary angioedema gives us hope kinin receptors antagonists could be more robustly tested for a possible clinical application in the treatment of pathological pains, which present limited pharmacology management.

Diosmetin, a novel transient receptor potential vanilloid 1 antagonist, alleviates the UVB radiation-induced skin inflammation in mice.

UVB radiation-mediated inflammation and the oxidative process involve the transient receptor potential vanilloid 1 (TRPV1) channel activation in neuronal and non-neuronal cells. Once diosmetin has been identified as a novel TRPV1 antagonist, we evaluated the action of diosmetin from the inflammatory [ear oedema, myeloperoxidase (MPO) activity, histological changes, and cytokines levels] and oxidative [nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and SOD activities] parameters in mice exposed to UVB radiation (0.5 j/cm2). We also verified the action of diosmetin on UVB radiation-induced inflammatory parameters after cutaneous nerve fibers denervation by RTX (50 µg/kg s.c.). The topical treatment with the novel TRPV1 antagonist, diosmetin (1%; 15 mg/ear), reduced ear oedema, MPO activity, and MIP-2 and IL-1ß cytokines levels by 82 ± 8%, 59 ± 10%, 40 ± 12%, and 85 ± 9%, respectively. The action of diosmetin on ear oedema and inflammatory cell infiltration was histologically confirmed. Topical diosmetin (1%) also reduced NADPH oxidase activity by 67 ± 10% and reverted SOD activity by 81 ± 13%. After cutaneous nerve fibers denervation using RTX, diosmetin reduced ear oedema, but not the inflammatory cell infiltration in mice exposed to UVB radiation. Diosmetin can be a promising molecule against skin inflammatory disorders as a result of sunburn induced by UVB radiation exposure.

Inhibitors of angiotensin I converting enzyme potentiate fibromyalgia-like pain symptoms via kinin receptors in mice.

Fibromyalgia is a potentially disabling chronic disease, characterized by widespread pain and a range of comorbidities such as hypertension. Among the mechanisms involved in fibromyalgia-like pain symptoms are kinins and their B1 and B2 receptors. Moreover, angiotensin I converting enzyme (ACE) inhibitors, commonly used as antihypertensive drugs, can enhance pain by blocking the degradation of peptides such as substance P and bradykinin, besides enhancing kinin receptors signalling. We investigated the effect of ACE inhibitors on reserpine-induced fibromyalgia-like pain symptoms and the involvement of kinins in this effect in mice. Nociceptive parameters (mechanical and cold allodynia and overt nociception) were evaluated after ACE inhibitors administration in mice previously treated with reserpine. The role of kinin B1 and B2 receptors was investigated using pharmacological antagonism. Additionally, bradykinin levels, as well as the activity of ACE and kininase I, were measured in the sciatic nerve, spinal cord and cerebral cortex of the mice. The ACE inhibitors enalapril and captopril enhanced reserpine-induced mechanical allodynia, and this increase was prevented by kinin B1 and B2 receptor antagonists. Substance P and bradykinin caused overt nociception and increased mechanical allodynia in animals treated with reserpine. Reserpine plus ACE inhibitors increased bradykinin-related peptide levels and inhibited ACE activity in pain modulation structures. Since hypertension is a frequent comorbidity affecting fibromyalgia patients, hypertension treatment with ACE inhibitors in these patients should be reviewed once this could enhance fibromyalgia-like pain symptoms. Thus, the treatment of hypertensive patients with fibromyalgia could include other classes of antihypertensive drugs, different from ACE inhibitors.

Neuronal and non-neuronal transient receptor potential ankyrin 1 mediates UVB radiation-induced skin inflammation in mice.

AIMS: Neuronal and non-neuronal TRPA1 channel plays an active role in the pathogenesis of several skin inflammatory diseases. Although a recent study identified the TRPA1 channel activation upon UVB exposure, its role in inflammatory, oxidative, and proliferative processes underlying UVB radiation-induced sunburn was not yet fully understood. We evaluated the TRPA1 channel contribution in inflammatory, oxidative, and proliferative states on skin inflammation induced by UVB radiation in mice. MAIN METHODS: TRPA1 role was evaluated from inflammatory (ear edema, myeloperoxidase, and N-acetyl-ß-D-glycosaminidase activities, histological changes, and cytokines levels), proliferative (epidermal hyperplasia, PCNA, and TRPA1 levels), and oxidative (reactive oxygen intermediates measure, H2O2 quantification, and NADPH oxidase activity) parameters caused by UVB radiation single (0.5 J/cm2) or repeated (0.1 J/cm2) exposure. We verified the contribution of non-neuronal and neuronal TRPA1 on UVB radiation-induced inflammatory parameters using RTX-denervation (50 µg/kg s.c.). KEY FINDINGS: TRPA1 blockade by the selective antagonist Lanette® N HC-030031 reduced all parameters induced by UVB radiation single (at concentration of 1%) or repeated (at concentration of 0.1%) exposure. We evidenced an up-regulation of the TRPA1 protein after UVB radiation repeated exposure, which was blocked by topical Lanette® N HC-030031 (0.1%). By RTX-denervation, we verified that non-neuronal TRPA1 also interferes in some inflammatory parameters induction. However, cutaneous nerve fibers seem to be most needed in the development of UVB radiation-induced inflammatory processes. SIGNIFICANCE: We propose the TRPA1 channel participates in the UVB radiation-induced sunburn in mice, and it could be a promising therapeutic target to treat skin inflammatory disorders.

Impacts of dose and length of exposure to boldenone and stanazolol on enzymatic antioxidant systems, myeloperoxidase and NAGase activities, and glycogen and lactate levels in rat liver.

We investigated the adverse effects of the anabolic androgenic steroids (AAS) boldenone (BOL) and stanazolol (ST) on the enzymatic antioxidant systems of the rat liver. Male Wistar rats were divided in three protocols (P): PI, 5 mg/kg BOL or ST once a week for 4 weeks; PII, 2.5 mg/kg BOL or ST once a week for 8 weeks; PIII, 1.25 mg/kg BOL or ST once a week for 12 weeks. AAS were administered intramuscularly (0.2 ml, olive oil vehicle) once a week in all protocols. Activities of the enzymes glutathione peroxidase (GPx), glutathione S-transferase (GST), and glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), were investigated. We assessed the content of hydrogen peroxide (H2O2), glycogen and lactate; and enzyme markers of neutrophils (myeloperoxidase, MPO) and macrophages (NAGase). PI and PII altered the SOD and CAT activities and increased the H2O2 content. PI led to increases in the MPO and NAGase activities. In contrast, changes in GPx, GST and, GR were observed under PII and, to a greater extend, under PIII. Following PIII, GPx, GR, and GST exhibited reduced activities. All protocols altered the glycogen and lactate content. The use of high doses of AAS for a short duration first alters SOD/CAT activity. In contrast, at lower doses of AAS for long periods is associated with changes in the glutathione system. Protocols with high doses of AAS for a short duration exert the most deleterious effects on redox status, markers of cellular infiltration, and the metabolic functioning of hepatic tissues.

Efficacy of the World Health Organization analgesic ladder in the paclitaxel-induced pain syndrome in rats.

Paclitaxel use in cancer treatment is limited by a painful syndrome that has no effective treatment. Despite new therapies, drugs of the World Health Organization (WHO) analgesic ladder remain a useful therapeutic tool for cancer pain relief. Since cancer pain is caused by both tumor and chemotherapy, we assessed the efficacy of drugs from the WHO analgesic ladder for cancer pain relief in a paclitaxel-induced pain syndrome (P-IPS) model. P-IPS was induced in rats by one or four injections of paclitaxel on alternate days. The acute and chronic phases were assessed 24 h and 15 days after the first paclitaxel injection, respectively. The mechanical allodynia was evaluated after (step 1 of the ladder) paracetamol, (step 2) codeine alone or plus paracetamol and (step 3) morphine treatment in the acute or chronic phase of P-IPS. Paracetamol, codeine and morphine were equally efficacious in reducing the acute phase of the P-IPS. Codeine plus paracetamol had similar efficacy and potency when administered together in the acute phase of the P-IPS, but produced a longer-lasting effect than when separately managed. Moreover, paracetamol, codeine and morphine partially reduced the chronic phase of P-IPS, losing their efficacy and, in the case of codeine, potency when compared to the acute phase. However, paracetamol plus codeine increased the potency and efficacy of the codeine when compared to codeine administered alone in the chronic phase of P-IPS, producing a long-lasting anti-allodynic effect. Together, analgesics of WHO analgesic ladder reduce both acute and chronic phases of P-IPS, with codeine plus paracetamol presenting more potent, efficacious and long-lasting effect. Thus, in addition to tumor pain, drugs of WHO analgesics ladder could also be useful to treat P-IPS.

Involvement of TRPV1 and the efficacy of α-spinasterol on experimental fibromyalgia symptoms in mice.

Fibromyalgia is characterised mainly by symptoms of chronic widespread pain and comorbidities like depression. Although these symptoms cause a notable impact on the patient's quality of life, the underlying aetiology and pathophysiology of this disease remain incompletely elucidated. The transient receptor potential vanilloid type 1 (TRPV1) is a polymodal receptor that is involved in the development of nociceptive and depressive behaviours, while α-spinasterol, a multitarget TRPV1 antagonist and cyclooxygenase inhibitor, presents antinociceptive and antidepressant effects. The present study investigated the involvement of the TRPV1 channel and the possible effects of α-spinasterol on nociceptive and depressive-like behaviours in an experimental fibromyalgia model. The fibromyalgia model was induced with a subcutaneous (s.c.) injection of reserpine (1 mg/kg) once daily for 3 consecutive days in male Swiss mice. Reserpine administration depleted monoamines and caused mechanical allodynia. This dysfunction was inhibited by SB-366791 (1 mg/kg, oral route [p.o.]), a selective TRPV1 antagonist, with a maximum inhibition (Imax) of 73.4 ± 15.5%, or by the single or 3-day-repeated administration of α-spinasterol (0.3 mg/kg, p.o.), with an Imax of 72.8 ± 17.8% and 78.9 ± 32.9%, respectively. SB-366791 also inhibited the increase of the reserpine-induced immobility time, with an Imax of 100%, while α-spinasterol inhibited this parameter with an Imax of 98.2 ± 21.5% and 100%, by single or repeated administration, respectively. The reserpine-induced mechanical allodynia and the thermal hyperalgesia were abolished by TRPV1-positive fibers desensitization induced by previous resiniferatoxin (RTX) administration. In summary, the TRPV1 channel is involved in the development and maintenance of nociception and depressive-like behaviours in a fibromyalgia model, while the α-spinasterol has therapeutic potential to treat the pain and depression symptoms in fibromyalgia patients.

Copaiba oleoresin has topical antinociceptive activity in a UVB radiation-induced skin-burn model in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Copaiba oleoresin, extracted from Copaifera L., is used as a wound healing, analgesic, antimicrobial and, mainly, anti-inflammatory agent. Thus, in this study we investigated the antinociceptive and anti-inflammatory effects of a topical formulation containing Copaiba oleoresin (3%) in a UVB radiation-induced skin burn model (0.75 J/cm2) in mice and performed a cream-formulation stability study. MATERIALS AND METHODS: The chemical composition of Copaiba oleoresin was analyzed using gas chromatography (GC-MS). The topical antinociceptive (evaluated through mechanical allodynia and thermal hyperalgesia) and the anti-inflammatory (dermal thickness and inflammatory cell infiltration) effects of treatments were assessed. The cream-formulation stability study was performed after two months, and organoleptic characteristics, pH, spreadability and rheological characteristics were analyzed. RESULTS: Copaiba oleoresin cream was able to prevent UVB radiation-induced mechanical allodynia on the 2nd, 3rd and 4th day after UVB radiation exposure with a maximum inhibition (Imax) of 64.6 ± 7% observed on the 2nd day; it also reduced the thermal hyperalgesia on the 1st and 2nd days post UVB radiation, with a Imax of 100% observed on the 2nd day. Moreover, topical treatment with Copaiba oleoresin cream inhibited the inflammatory cell infiltration, but did not reduce the dermal thickness. Such effects can be attributed, at least in part, to the presence of biological components, such as ß-caryophyllene and other sesquiterpenes identified by GC-MS. CONCLUSION: Our results demonstrate that the topical formulation containing Copaiba oleoresin presented antinociceptive and anti-inflammatory effects in mice subjected to a UVB radiation and that the cream-formulation was stable for two months. Thus, use of Copaiba oleoresin is a promising strategy for the treatment of inflammatory pain associated with sunburn.

Dacarbazine alone or associated with melanoma-bearing cancer pain model induces painful hypersensitivity by TRPA1 activation in mice.

Antineoplastic therapy has been associated with pain syndrome development characterized by acute and chronic pain. The chemotherapeutic agent dacarbazine, used mainly to treat metastatic melanoma, is reported to cause painful symptoms, compromising patient quality of life. Evidence has proposed that transient receptor potential ankyrin 1 (TRPA1) plays a critical role in chemotherapy-induced pain syndrome. Here, we investigated whether dacarbazine causes painful hypersensitivity in naive or melanoma-bearing mice and the involvement of TRPA1 in these models. Mouse dorsal root ganglion (DRG) neurons and human TRPA1-transfected HEK293 (hTRPA1-HEK293) cells were used to evaluate the TRPA1-mediated calcium response evoked by dacarbazine. Mechanical and cold allodynia were evaluated after acute or repeated dacarbazine administration in naive mice or after inoculation of B16-F10 melanoma cells in C57BL/6 mice. TRPA1 involvement was investigated by using pharmacological and genetic tools (selective antagonist or antisense oligonucleotide treatment and Trpa1 knockout mice). Dacarbazine directly activated TRPA1 in hTRPA1-HEK293 cells and mouse DRG neurons and appears to sensitize TRPA1 indirectly by generating oxidative stress products. Moreover, dacarbazine caused mechanical and cold allodynia in naive but not Trpa1 knockout mice. Also, dacarbazine-induced nociception was reduced by the pharmacological TRPA1 blockade (antagonism), antioxidants, and by ablation of TRPA1 expression. TRPA1 pharmacological blockade also reduced dacarbazine-induced nociception in a tumor-associated pain model. Thus, dacarbazine causes nociception by TRPA1 activation, indicating that this receptor may represent a pharmacological target for treating chemotherapy-induced pain syndrome in cancer patients submitted to antineoplastic treatment with dacarbazine.

Kinins and their B1 and B2 receptors are involved in fibromyalgia-like pain symptoms in mice.

Fibromyalgia is a disease characterised as generalised chronic primary pain that causes functional disability and a reduction in patients' quality of life, without specific pathophysiology or appropriate treatment. Previous studies have shown that kinins and their B1 and B2 receptors contribute to chronic painful conditions. Thus, we investigated the involvement of kinins and their B1 and B2 receptors in a fibromyalgia-like pain model induced by reserpine in mice. Nociceptive parameters (mechanical allodynia, cold sensitivity and overt nociception) and behaviours of burrowing, thigmotaxis, and forced swimming were evaluated after reserpine administration in mice. The role of kinin B1 and B2 receptors was investigated using knockout mice or pharmacological antagonism. The protein expression of kinin B1 and B2 receptors and the levels of bradykinin and monoamines were measured in the sciatic nerve, spinal cord and cerebral cortex of the animals. Knockout mice for the kinin B1 and B2 receptor reduced reserpine-induced mechanical allodynia. Antagonism of B1 and B2 receptors also reduced mechanical allodynia, cold sensitivity and overt nociception reserpine-induced. Reserpine altered thigmotaxis, forced swimming and burrowing behaviour in the animals; with the latter being reversed by antagonism of kinin B1 receptor. Moreover, reserpine increased the protein expression of kinin B1 and B2 receptors and levels of kinin, as well as reduced the levels of monoamines in peripheral and central structures. Kinins and its B1 and B2 receptors are involved in fibromyalgia-like pain symptoms. B1 or B2 receptors might represent a potential target for the relief of fibromyalgia-like pain symptoms.

Persea americana Mill. crude extract exhibits antinociceptive effect on UVB radiation-induced skin injury in mice.

Persea americana, popularly known as avocado, has been empirically used as analgesic and anti-inflammatory including in the skin disorder treatment. Species of the genus Persea also show a photoprotective effect against UVB radiation. We investigated the antinociceptive and anti-inflammatory effects from a topical formulation containing the P. americana leaf extract in a UVB irradiation-induced burn model in mice and performed a gel-formulation stability study. The antinociceptive and anti-inflammatory effect was evaluated through mechanical allodynia, paw oedema, and inflammatory cell infiltration. Phenolic compounds were quantified by UHPLC-MS/MS. The gel-formulation stability study was performed analyzing organoleptic characteristics, pH, and viscosity. P. americana (3%) gel was able to prevent the UVB irradiation-induced mechanical allodynia on the 2nd and 3rd day after irradiation with maximum inhibition of 60 ± 12% at 2nd day. Such effect may be attributed, at least in part, due the presence of (+)-catechin (302.2 ± 4.9 µg/g) followed by chlorogenic acid (130 ± 5.1 µg/g) and rutin (102.4 ± 0.9 µg/g) found in the extract. The gel was not able to prevent the inflammatory parameters such as edema and leukocyte infiltration induced by UVB irradiation. No changes important were detected in the stability study, mainly in low temperature. Our results suggest that P. americana gel-formulation, which presented stability, ensuring its quality and the therapeutic effect, could be an interesting strategy for the treatment of the pain associated with sunburn; this effect could be attributed to its biological constituents, especially catechin, chlorogenic acid, and rutin.

Nasturtium officinale R. Br. effectively reduces the skin inflammation induced by croton oil via glucocorticoid receptor-dependent and NF-κB pathways without causing toxicological effects in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Inflammatory skin diseases treatments currently used cause adverse effects. Nasturtium officinale (watercress) is used popularly as an anti-inflammatory. However, until now, no study proved its effectiveness as a topical treatment to inflammatory skin diseases. The topical anti-inflammatory activity of N. officinale crude extract leaves (NoE) on an irritant contact dermatitis (ICD) model croton oil-induced in mice was investigated. MATERIALS AND METHODS: ICD models were induced by a single (1 mg/ear; acute) or repeated (0.4 mg/ear; chronic; 9 days total) croton oil application. NoE and dexamethasone solutions' (diluted in acetone; 20 µL/ear) or NoE gel, dexamethasone gel and base gel (15 mg/ear) were topically applied immediately after croton oil application. The NoE topical anti-inflammatory effect was evaluated for inflammatory parameters (ear edema, inflammatory cells infiltration, and inflammatory cytokines levels). NoE topical anti-inflammatory mechanism (NF-κB pathway and effect glucocorticoid-like) were assessed by western blot and ear edema analyses, respectively. UHPLC-MS/MS chromatography, gels accelerated stability and preliminary study of adverse effects was also performed. RESULTS: UHPLC-MS/MS of the NoE revealed the presence of coumaric acid, rutin, and ferulic acid. NoE gels stability study showed no relevant changes at low temperature. NoE, dexamethasone, NoE gel and dexamethasone gel inhibited the ear edema croton oil-induced by 82 ±â€¯6% (1 mg/ear), 99 ±â€¯1% (0.1 mg/ear), 81 ±â€¯8% (3%) and 70 ±â€¯6% (0.5%) for the acute model, and 49 ±â€¯7% (1 mg/ear), 80 ±â€¯4% (0.1 mg/ear), 41 ±â€¯8% (3%) and 46 ±â€¯14% (0.5%) for the chronic model, respectively. The same treatments also reduced the inflammatory cells infiltration by 62 ±â€¯3% (1 mg/ear), 97 ±â€¯2% (0.1 mg/ear), 60 ±â€¯3% (3%) and 66 ±â€¯6% (0.5%) for the acute model, respectively, and 25 ±â€¯8% (1 mg/ear) to NoE and 83 ±â€¯13% to dexamethasone to the chronic model. NoE and NoE gel reduced the pro-inflammatory cytokines levels (acute ICD model) by 62 ±â€¯5% and 71 ±â€¯3% (MIP-2) and 32 ±â€¯3% and 44 ±â€¯4% (IL-1ß), while dexamethasone solution's and gel reduced by 79 ±â€¯7% and 44 ±â€¯4% to MIP-2 and 98 ±â€¯2% and 83 ±â€¯9% to IL-1ß, respectively. NoE' and dexamethasone' solutions inhibited the reduction of IkB-α protein expression induced by croton oil by 100% and 80 ±â€¯14%, respectively. Besides, the mifepristone (glucocorticoid receptor antagonist) pre-treatment prevented the topical anti-edematogenic effect of NoE' and dexamethasone' solutions by 61 ±â€¯5% to NoE and 78 ±â€¯16% to dexamethasone. The repeated topical application of NoE did not cause adverse effects. CONCLUSION: Our results suggest the N. officinale use in the cutaneous inflammatory process treatment and demonstrate the NoE potential to develop a promising topical anti-inflammatory agent to treat inflammatory disorders.

α-Spinasterol: a COX inhibitor and a transient receptor potential vanilloid 1 antagonist presents an antinociceptive effect in clinically relevant models of pain in mice.

BACKGROUND AND PURPOSE: Postoperative pain is one of the most common manifestations of acute pain and is an important problem faced by patients after surgery. Moreover, neuronal trauma or chemotherapeutic treatment often causes neuropathic pain, which induces disabling and distressing symptoms. At present, treatments of both painful conditions are inadequate. α-Spinasterol, which is well characterized as a transient receptor potential vanilloid 1 antagonist, has anti-inflammatory, antioxidant and antinociceptive effects. Therefore, we investigated its antinociceptive potential on postoperative and neuropathic pain, as well as its effect on COX-1 and COX-2 activities. EXPERIMENTAL APPROACH: Nociceptive responses in a postoperative pain model (surgical incision-induced) or different neuropathic pain models (trauma or chemotherapy-induced) were investigated in mice. KEY RESULTS: Oral administration of α-spinasterol reduced postoperative pain, when given as a pre- (0.5 h before incision) or post-treatment (0.5 h after incision), and reduced cell infiltration in the injured tissue. α-Spinasterol also reduced the mechanical allodynia induced by partial sciatic nerve ligation and the mechanical and cold allodynia induced by paclitaxel. Moreover, α-spinasterol inhibited COX-1 and COX-2 enzyme activities without altering the body temperature of animals. Importantly, α-spinasterol did not alter spontaneous or forced locomotor activity. Furthermore, it did not cause gastric damage or liver and kidney changes, nor did it alter cell viability in the cerebral cortex and spinal cord slices of mice. CONCLUSION AND IMPLICATIONS: α-Spinasterol is an effective and safe COX inhibitor with antinociceptive effects in postoperative and neuropathic pain models. Therefore, it is an interesting prototype for the development of novel analgesic drugs.

Potentiation of Paclitaxel-Induced Pain Syndrome in Mice by Angiotensin I Converting Enzyme Inhibition and Involvement of Kinins.

Paclitaxel is a chemotherapeutic agent used to treat solid tumours. However, it causes an acute and neuropathic pain syndrome that limits its use. Among the mechanisms involved in neuropathic pain caused by paclitaxel is activation of kinin receptors. Angiotensin converting enzyme (ACE) inhibitors can enhance kinin receptor signalling. The goal of this study was to evaluate the role of kinins on paclitaxel-associated acute pain syndromes (P-APS) and the effect of ACE inhibition on P-APS and paclitaxel-associated chronic peripheral neuropathy (P-CPN) in mice. Herein, we show that paclitaxel caused mechanical allodynia and spontaneous nociceptive behaviour that was reduced by antagonists of kinin receptors B1 (DALBk and SSR240612) and B2 (Hoe140 and FR173657). Moreover, enalapril (an ACE inhibitor) enhanced the mechanical allodynia induced by a low dose of paclitaxel. Likewise, paclitaxel injection inhibited ACE activity and increased the expressions of B1 and B2 receptors and bradykinin-related peptides levels in peripheral tissue. Together, our data support the involvement of kinin receptors in the P-APS and suggest kinin receptor antagonists to treat this syndrome. Because hypertension is the most frequent comorbidity affecting cancer patients, treatment of hypertension with ACE inhibitors in patients undergoing paclitaxel chemotherapy should be reviewed, since this could enhance the P-APS and P-CPN.

In vitro and in vivo evaluation of a desonide gel-cream photostabilized with benzophenone-3.

CONTEXT: Our group previously reported the photoinstability of some desonide topical commercial formulations under direct exposure to UVA radiation. OBJECTIVE: This study aimed to prepare and characterize a gel-cream containing desonide, with greater photostability than the commercial gel-cream (C-GC). Benzophenone-3 (BP-3) was used as a photostabilizing agent. METHODS: The gel-cream developed (D-GC) containing BP-3 at 0.1% was prepared and characterized regarding its pH, drug content, spreadability, viscosity, in vitro drug release and in vitro permeation. The in vivo anti-inflammatory effect was assessed by ear edema measurement, croton oil-induced acute skin inflammation and myeloperoxidase assay. RESULTS AND DISCUSSION: D-GC presented characteristics compatible with topical application, appropriate drug content and good spreadability, and non-Newtonian behavior with pseudoplastic flow. D-GC showed a good photostability profile, presenting a desonide content of 95.70% after 48 h of exposure to UVA radiation, and stability under room conditions during 60 days. The amount of desonide released from D-GC and C-GC was 57.8 and 51.7 µg/cm2, respectively, measured using the vertical Franz cell. The in vitro skin permeation showed that desonide reached the site of action of the topical corticosteroids, from both formulations; however, the desonide amount retained in the dermis was lower with D-GC. The in vivo evaluation of topical anti-inflammatory activity indicated that D-GC presented the same biological effect as C-GC. CONCLUSION: D-GC represents a promising approach to treat dermatological disorders, since it presented satisfactory physicochemical characteristics, the same biological activity as C-GC and superior photostability, conferred by the addition of BP-3 at 0.1%.