The Anti-Inflammatory and Anti-Pruritus Mechanisms of Huanglian Jiedu Decoction in the Treatment of Atopic Dermatitis

Liangxue Qushi Zhiyang Decoction Inhibits Atopic Dermatitis in Mice via FcγR-Mediated Phagocytosis

Background: Liangxue Qushi Zhiyang Decoction (LQZ) is a traditional formula known for its efficacy in treating Atopic Dermatitis (AD). However, the specific mechanisms through which LQZ alleviates AD symptoms remain largely unknown. The objective of this study is to investigate the protective effects of LQZ on AD and to uncover its potential mechanisms of action. Methods: An AD model was established in mice using 2,4-dinitrochlorobenzene (DNCB). Mice were then orally administered LQZ or prednisolone (PDN). Throughout the treatment period, dermatitis scores and scratching frequencies of the mice were regularly monitored. Histopathological analyses were conducted using hematoxylin and eosin (H&E) staining and toluidine blue (TB) staining. Serum levels of inflammatory cytokines were measured using enzyme-linked immunosorbent assay (ELISA). Further, tandem mass tag (TMT) labeling quantitative proteomics was employed to identify differentially expressed proteins (DEPs). Enrichment analysis was conducted to pinpoint potential targets and pathways involved in LQZ's therapeutic action. Finally, validation experiments were performed to further explore the specific pathways and core targets of LQZ in AD treatment.. Results: LQZ treatment notably mitigated the skin barrier damage and inflammatory response induced by DNCB in AD mice, and reduced the serum levels of IgE, IL-4, and IL-1β. Proteomic analysis identified 248 proteins with differential expression, implicating multiple pathways in LQZ' therapeutic action. Among these, the Fc gamma R(FcγR)-mediated phagocytosis pathway emerged as a crucial factor in AD's inflammatory and immune responses. Key proteins associated with this pathway, including Fc-gamma RIII (Fcgr3), V-yes-1 Yamaguchi sarcoma viral related oncogene homolog (Lyn), Tyrosine-protein kinase (Syk), Phosphoinositide phospholipase C-gamma-2 (Plcg2), Neutrophil cytosol factor 1 (Ncf1), Ras-related C3 botulinum toxin substrate 2 (Rac2) and Actin-related protein 2/3 complex subunit 3 (Arpc3), exhibited significantly reduced expression levels following LQZ treatment. Conclusion: LQZ is effective in treating AD by alleviating skin barrier damage and inflammatory reactions. Its anti-AD properties of LQZ may be attributed to the inhibition of the FcγR-mediated phagocytic pathway.

Oleoylethanolamide ameliorates allergic asthma and atopic dermatitis via activation of GPR119

Serum levels of oleoylethanolamide (OEA) have been associated with the severity of pulmonary diseases, and augmented levels of epidermal OEA have been observed in response to low-grade inflammation in human skin. OEA acts as an endogenous ligand for GPR119; thus, the functional roles of GPR119 were investigated using two murine models. We tested effects of OEA and AR231453, a selective synthetic GPR119 agonist on ovalbumin (OVA)-induced allergic asthma and 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis-like models in GPR119 wild-type (WT) and deficient mice. In OVA-induced allergic asthma model, administration of OEA or AR231453 reduced allergic feature, including airway hyperresponsiveness, eosinophil accumulation in bronchoalveolar lavage fluid, airway inflammation, and mucin secretion in the lungs, and both ameliorated DNCB-induced atopic dermatitis-like skin lesions, such as hypertrophy and mast cell accumulation, in GPR119 wild-type (WT) mice, but not in GPR119-deficient mice. OEA or AR231453 treatment reduced OVA-induced increase in pro-inflammatory cytokine expression, and type 2 innate lymphoid cells in the lungs, and both significantly suppressed the DNCB-induced lymph node enlargement and inflammatory Th2/1/17 cells in GPR119 WT mice, but not in GPR119-deficient mice. In RBL-2H3 mast cells, OEA or AR231453 suppressed degranulation and Th2 cytokine expression. These findings suggest that OEA functions to protect against allergic asthma and atopic dermatitis via GPR119 activation by suppressing immune responses in the lungs, lymph nodes, and skin, highlighting GPR119 activation as a therapeutic target for allergic and inflammatory diseases.

Seborrheic Dermatitis Treatment Using a Standardized Medical Insurance-Approved Korean Medicine: a case report

Background

Conventional treatments for seborrheic dermatitis often lead to a recurring cycle of symptom improvement and worsening, resulting in chronic conditions. Thus, safer and more effective alternatives are needed. In Korean medicine, Hwangryunhaedok-tang tablets, targeted at treating the fire-heat syndrome, offer a more fundamental approach to manage seborrheic dermatitis.

Clinical Features and Outcomes

In this study, we monitored the changes in the symptoms of two patients with seborrheic dermatitis who were treated with Hwangryunhaedok-tang tablets. The patients were administered this medication during the treatment period. The effectiveness of the treatment was assessed by visually recording changes in the affected skin areas using photographs and evaluating symptoms such as heat, itching, and stinging in these areas using a visual analog scale (VAS). Visible improvements in the patients' skin conditions were observed after taking Hwangryunhaedok-tang tablets. Following treatment, VAS scores for subjective symptoms such as heat sensation, itching, and stinging in the affected areas decreased.

Conclusion

This study offers evidence of a potential alternative approach for treating seborrheic dermatitis using Kyungbang Hwangryunhaedok-tang tablets. However, it highlights the necessity for further research on the appropriate dosage, side effects, and long-term effectiveness of this treatment.

Huanglian Jiedu decoction inhibits vascular smooth muscle cell-derived foam cell formation by activating autophagy via suppressing P2RY12

ETHNOPHARMACOLOGICAL RELEVANCE

Huanglian Jiedu Decoction (HLJDD) is a Chinese medicine with a long history of therapeutic application. It is widely used in treating atherosclerosis (AS) in Chinese medicine theory and clinical practice. However, the mechanism of HLJDD in treating AS remains unclear.

AIM OF THE STUDY

To investigate the efficacy and mechanism of HLJDD in treating AS.

MATERIALS AND METHODS

AS was induced on high-fat diet-fed ApoE-/- mice, with the aorta pathological changes evaluated with lipid content and plaque progression. In vitro, foam cells were induced by subjecting primary mouse aortic vascular smooth muscle cells (VSMCs) to oxLDL incubation. After HLJDD intervention, VSMCs were assessed with lipid stack, apoptosis, oxidative stress, and the expression of foam cell markers. The effects of P2RY12 were tested by adopting clopidogrel hydrogen sulfate (CDL) in vivo and transfecting P2RY12 over-expressive plasmid in vitro. Autophagy was inhibited by Chloroquine or transfecting siRNA targeting ATG7 (siATG7). The mechanism of HLJDD treating atherosclerosis was explored using network pharmacology and validated with molecular docking and co-immunoprecipitation.

RESULTS

HLJDD exhibited a dose-dependent reduction in lipid deposition, collagen loss, and necrosis within plaques. It also reversed lipid accumulation and down-regulated the expression of foam cell markers. P2RY12 inhibition alleviated AS, while P2RY12 overexpression enhanced foam cell formation and blocked the therapeutic effects of HLJDD. Network pharmacological analysis suggested that HLJDD might mediate PI3K/AKT signaling pathway-induced autophagy. P2RY12 overexpression also impaired autophagy. Similarly, inhibiting autophagy counteracted the effect of CDL, exacerbated AS in vivo, and promoted foam cell formation in vitro. However, HLJDD treatment mitigated these detrimental effects by suppressing the PI3K/AKT signaling pathway. Immunofluorescence and molecular docking revealed a high affinity between P2RY12 and PIK3CB, while co-immunoprecipitation assays illustrated their interaction.

CONCLUSIONS

HLJDD inhibited AS in vivo and foam cell formation in vitro by restoring P2RY12/PI3K/AKT signaling pathway-suppressed autophagy. This study is the first to reveal an interaction between P2RY12 and PI3K3CB.

Unraveling the treatment effects of huanglian jiedu decoction on drug-induced liver injury based on network pharmacology, molecular docking and experimental validation

Huanglian Jiedu Decoction (HJD) is a well-known Traditional Chinese Medicine formula that has been used for liver protection in thousands of years. However, the therapeutic effects and mechanisms of HJD in treating drug-induced liver injury (DILI) remain unknown. In this study, a total of 26 genes related to both HJD and DILI were identified, which are corresponding to a total of 41 potential active compounds in HJD. KEGG analysis revealed that Tryptophan metabolism pathway is particularly important. The overlapped genes from KEGG and GO analysis indicated the significance of CYP1A1, CYP1A2, and CYP1B1. Experimental results confirmed that HJD has a protective effect on DILI through Tryptophan metabolism pathway. In addition, the active ingredients Corymbosin, and Moslosooflavone were found to have relative strong intensity in UPLC-Q-TOF-MS/MS analysis, showing interactions with CYP1A1, CYP1A2, and CYP1B1 through molecule docking. These findings could provide insights into the treatment effects of HJD on DILI.

Buyang Huanwu Decoction suppresses cardiac inflammation and fibrosis in mice after myocardial infarction through inhibition of the TLR4 signalling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

It has been reported that cardiac inflammation and fibrosis participate in the development of heart failure (HF) following myocardial infarction (MI). Anti-inflammatory and anti-fibrotic treatments exhibit therapeutic efficacy in MI. Buyang Huanwu Decoction (BYHWD) has cardioprotective properties. However, whether BYHWD regulates cardiac inflammation and fibrosis in HF after MI, and the underlying mechanisms, are still unknown.

AIM OF THE STUDY

This study aimed to explore the effects and potential mechanisms of BYHWD on cardiac inflammation and fibrosis after MI.

MATERIALS AND METHODS

An MI model was constructed through ligation of the left anterior descending coronary artery (LAD) in mice. The cardioprotective effects of BYHWD were determined by echocardiography, Masson trichrome staining, wheat germ agglutinin (WGA) staining and haematoxylin and eosin (HE) staining. The effects of BYHWD on inflammation and fibrosis, and on the TLR4 signalling pathway, were explored through immunohistochemistry (IHC), Western blot (WB), enzyme-linked immunosorbent assay (ELISA) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) in vivo. Next, the effects of BYHWD on primary cardiac fibroblasts (CFs) inflammation and collagen synthesis, and on the TLR4 signalling pathway, were detected using WB, immunofluorescence (IF) and qRT-PCR in vitro. In addition, the suppression and overexpression of TLR4 in CFs were further explored.

RESULTS

BYHWD dose-dependently reduced cardiac inflammation, fibrosis and ventricular dysfunction. The expression levels of collagen Ⅰ/Ⅲ, IL-1β and IL-18, as well as critical proteins in the TLR4 signalling pathway and the NLRP3 inflammasome, were suppressed by BYHWD in the in vivo experiment. BYHWD inhibited CFs inflammation and collagen synthesis, as well as critical proteins in the TLR4 signalling pathway and the NLRP3 inflammasome, in the in vitro experiment. TLR4 suppression mitigated these inhibitory effects of BYHWD while overexpression of TLR4 markedly reversed these inhibitory effects of BYHWD.

CONCLUSION

BYHWD exerts anti-inflammatory and anti-fibrotic effects in mice after MI, and suppresses CFs inflammation and collagen synthesis through suppression of the TLR4 signalling pathway.

Palmatine ameliorated lipopolysaccharide-induced sepsis-associated encephalopathy mice by regulating the microbiota-gut-brain axis

BACKGROUND

Sepsis-associated encephalopathy (SAE), a common neurological complication from sepsis, is widespread among patients in intensive care unit and is linked to substantial morbidity and mortality rates, thus posing a substantial menace to human health. Due to the intricate nature of SAE's pathogenesis, there remains a dearth of efficacious therapeutic protocols, encompassing pharmaceutical agents and treatment modalities, up until the present time. Palmatine exhibits distinctive benefits in the regulation of inflammation for the improvement of sepsis. Nevertheless, the precise functions of palmatine in treating SAE and its underlying mechanism have yet to be elucidated.

PURPOSE

This study aimed to evaluate efficiency of palmatine in SAE mice and its underlying mechanisms.

STUDY DESIGN AND METHODS

Behavioral experiments, percent survival rate analysis, histological analysis, immunofluorescence staining, ELISA analysis, were performed to evaluate the efficiency of palmatine in SAE mice. Quantibody® mouse inflammation array glass chip was performed to observe the effects of palmatine on inflammation storm in SAE mice. Real-time quantitative and western blotting analyzes were employed to examine the expression of relevant targets in the Notch1/nuclear factor-kappa B (NF-κB) pathway. Finally, brain tissues metabolomics-based analyzes were performed to detect the differentially expressed metabolites and metabolic pathways. The fecal samples were subjected to microbial 16S rRNA analysis and untargeted metabolomics analysis in order to identify the specific flora and metabolites associated with SAE, thereby further investigating the mechanism of palmatine in SAE mice.

RESULTS

Our results showed that palmatine significantly improved nerve function, reduced cell apoptosis in brain tissue, and decreased inflammatory cytokine levels in SAE induced-LPS mice. Meanwhile, our results demonstrate the potential of palmatine in modulating key components of the Notch1/NF-κB pathway, enhancing the expression of tight junction proteins, improving intestinal permeability, promoting the growth of beneficial bacteria (such as Lachnospiraceae_NK4A136_group), inhibiting the proliferation of harmful bacteria (such as Escherichia-Shigella), and mitigating metabolic disorders. Ultimately, these observed effects contribute to the therapeutic efficacy of palmatine in treating SAE.

CONCLUSION

The findings of our study have provided confirmation regarding the efficacy of palmatine in the treatment of SAE, thereby establishing a solid foundation for further exploration into SAE therapy and the advancement and investigation of palmatine.

Synthesis, in silico modelling, and in vitro biological evaluation of substituted pyrazole derivatives as potential anti-skin cancer, anti-tyrosinase, and antioxidant agents

Twenty-five azole compounds (P1-P25) were synthesised using regioselective base-metal catalysed and microwave-assisted approaches, fully characterised by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR), and infrared spectra (IR) analyses, and evaluated for anticancer, anti-tyrosinase, and anti-oxidant activities in silico and in vitro. P25 exhibited potent anticancer activity against cells of four skin cancer (SC) lines, with selectivity for melanoma (A375, SK-Mel-28) or non-melanoma (A431, SCC-12) SC cells over non-cancerous HaCaT-keratinocytes. Clonogenic, scratch-wound, and immunoblotting assay data were consistent with anti-proliferative results, expression profiling therewith implicating intrinsic and extrinsic apoptosis activation. In a mushroom tyrosinase inhibition assay, P14 was most potent among the compounds (half-maximal inhibitory concentration where 50% of cells are dead, IC50 15.9 μM), with activity greater than arbutin and kojic acid. Also, P6 exhibited noteworthy free radical-scavenging activity. Furthermore, in silico docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET) simulations predicted prominent-phenotypic actives to engage diverse cancer/hyperpigmentation-related targets with relatively high affinities. Altogether, promising early-stage hits were identified - some with multiple activities - warranting further hit-to-lead optimisation chemistry with further biological evaluations, towards identifying new skin-cancer and skin-pigmentation renormalising agents.

Application and Effectiveness of Chinese Medicine in Regulating Immune Checkpoint Pathways

Immunotherapy targeting immune checkpoint molecules has emerged as a key approach in cancer treatment, representing the forefront of antitumor research. However, studies on immune checkpoint molecules have mainly focused on targeted therapies. Chinese medicine (CM) research as a complementary medicine has revealed that immune checkpoint molecules also undergo disease-specific changes in the context of autoimmune diseases. This review article presents a comprehensive analysis of CM studies on immune checkpoint molecules in the last 5 years, with a focus on their role in different diseases and treatment modalities. CM research predominantly utilizes oral administration of herbal plant extracts or acupuncture techniques, which stimulate the immune system by activating specific acupoints through temperature and needling. In this study, we analyzed the modulation and mechanisms of immune checkpoint molecules associated with different coinhibitory and costimulatory molecules, and reviewed the immune functions of related molecules and CM studies in treating autoimmune diseases and tumors. By summarizing the characteristics and research value of CM in regulating immune checkpoint molecules, this review aims to provide a useful reference for future studies in this field.

T cell co-stimulatory and co-inhibitory pathways in atopic dermatitis

The use of immune checkpoint inhibitors (ICIs) targeting the T cell inhibitory pathways has revolutionized cancer treatment. However, ICIs might induce progressive atopic dermatitis (AD) by affecting T cell reactivation. The critical role of T cells in AD pathogenesis is widely known. T cell co-signaling pathways regulate T cell activation, where co-signaling molecules are essential for determining the magnitude of the T cell response to antigens. Given the increasing use of ICIs in cancer treatment, a timely overview of the role of T cell co-signaling molecules in AD is required. In this review, we emphasize the importance of these molecules involved in AD pathogenesis. We also discuss the potential of targeting T cell co-signaling pathways to treat AD and present the unresolved issues and existing limitations. A better understanding of the T cell co-signaling pathways would aid investigation of the mechanism, prognosis evaluation, and treatment of AD.

Efficacy and safety of Chinese herbal medicine in the treatment of chronic pruritus: A systematic review and meta-analysis of randomized controlled trials

Background: Chronic pruritus (CP) is a common and aggravating symptom associated with skin and systemic diseases. Although clinical reports suggest that Chinese herbal medicine (CHM) is safe and effective in Chronic pruritus treatment, evidence to prove it is lacking. Therefore, in this review, we evaluated the therapeutic effects and safety of Chinese herbal medicine for the treatment of Chronic pruritus. Methods: Nine databases were searched for relevant randomized controlled trials (RCTs) from the inception of the database to 20 April 2022. The randomized controlled trials that compared the treatment of Chinese herbal medicine or a combination of Chinese herbal medicine and conventional western medicine treatment (WM) with western medicine treatment intervention for patients with Chronic pruritus were selected. We evaluated the effects of treatment with Chinese herbal medicine on the degree of pruritus, the Dermatology Life Quality Index (DLQI) score, response rate, recurrence rate, and incidence of adverse events in patients with Chronic pruritus. The risk of bias in each trial was evaluated using the Cochrane Collaboration tool. The RevMan software (version 5.3) was used for performing meta-analyses to determine the comparative effects. Results: Twenty-four randomized controlled trials were included, compared with placebo, moderate-quality evidence from one study showed that Chinese herbal medicine was associated with reduced visual analogue scale (VAS) (MD: -2.08; 95% CI = -2.34 to -1.82). Compared with western medicine treatment, low-to moderate-quality evidence from 8 studies indicated that Chinese herbal medicine was associated with reduced visual analogue scale, 4 studies indicated that Chinese herbal medicine was associated with reduced Dermatology Life Quality Index (MD = -1.80, 95% CI = -2.98 to -.62), and 7 studies indicated that Chinese herbal medicine was associated with improved Effective rate (RR: 1.26; 95% CI = 1.19-1.34). Compared with combination of Chinese herbal medicine and western medicine treatment, 16 studies indicated that Chinese herbal medicine was associated with reduced visual analogue scale, 4 studies indicated that Chinese herbal medicine was associated with reduced Dermatology Life Quality Index (MD = -2.37, 95% CI = -2.61 to -2.13), and 13 studies indicated that Chinese herbal medicine was associated with improved Effective rate (RR: 1.28; 95% CI = 1.21-1.36). No significant difference in the occurrence of adverse events in using Chinese herbal medicine or western medicine treatment was reported. Conclusion: The efficacy of Chinese herbal medicine used with or without western medicine treatment was better than western medicine treatment in treating chronic pruritus. However, only a few good studies are available regarding Chronic pruritus, and thus, high-quality studies are necessary to validate the conclusions of this study.

Chinese herbal bath therapy for the treatment of Atopic dermatitis in children: A meta-analysis and systematic review

BACKGROUND

To conduct a systematic review of the efficacy of Chinese herbal bath therapy on children with Atopic dermatitis.

METHODS

We searched Chinese databases (CNKI, VIP, and Wanfang) and English databases (PubMed, Embase, Web of science, Cochrane library) for studies from the establishment of the database to September 2022. The included literature was randomized control studies investigating the treatment of Atopic dermatitis in children by Chinese herbal bath therapy. The outcomes included the cure rate, scoring atopic dermatitis (SCORAD) index, adverse reactions and recurrence rate. RevMan 5.4 was used to analyze the extracted data.

RESULTS

A total of 8 related studies were included containing 854 cases. The meta-analysis showed that Chinese herbal bath therapy group was superior to control group in terms of cure rate, SCORAD index, adverse reactions and recurrence rate in children with Atopic dermatitis [RR = 1.11, 95%(1.02, 1.21), P = .01; SMD = -0.77, 95%(-0.99, -0.55), P < .00001; RR = 0.44, 95%CI(0.28,0.67), P = .0002; RR = 0.25, 95%CI(0.10, 0.59), P = .0002].

CONCLUSION

The present study shows that Chinese herbal bath therapy is an effective treatment for children with Atopic dermatitis in China.

Treatment Options for Troublesome Itch

Itch (or pruritus) is an unpleasant sensation, inducing the desire to scratch. It is also a major and distressing symptom of many skin and systemic diseases. The involvement of histamine, which is a major itch mediator, has been extensively examined. Recent studies suggest that histamine-independent pathways may play roles in chronic itch. Therefore, antihistamines are not always effective in the treatment of patients with chronic itch. The development of biologics and κ-opioid receptor (KOR) agonists has contributed to advances in the treatment of itch; however, since biologics are expensive for patients to purchase, some patients may limit or discontinue their use of these agents. Furthermore, KOR agonists need to be prescribed with caution due to risks of side effects in the central nervous system. Janus kinase (JAK) inhibitors are sometimes associated with side effects, such as infection. In this review, we summarize antidepressants, antineuralgics, cyclosporine A, antibiotics, crotamiton, phosphodiesterase 4 inhibitor, botulinum toxin type A, herbal medicines, phototherapy, and acupuncture therapy as itch treatment options other than antihistamines, biologics, opioids, and JAK inhibitors; we also explain their underlying mechanisms of action.

Portulaca oleracea L. extracts alleviate 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice

Atopic dermatitis (AD) is a common chronic allergic skin disease characterized clinically by severe skin lesions and pruritus. Portulaca oleracea L. (PO) is a resourceful plant with homologous properties in medicine and food. In this study, we used two different methods to extract PO, and compared the therapeutic effects of PO aqueous extract (POAE) and PO ultrasound-assisted ethanol extract (POEE) on 2,4-dinitrochlorobenzene (DNCB)-induced AD mice. The results showed that in POAE and POEE, the extraction rates of polysaccharides were 16.95% and 9.85%, while the extraction rates of total flavonoids were 3.15% and 3.25%, respectively. Compared with AD mice, clinical symptoms such as erythema, edema, dryness and ulceration in the back and left ear were alleviated, and pruritus behavior was reduced after POAE and POEE treatments. The thickness of the skin epidermis was thinned, the density of skin nerve fibers labeled with protein gene product 9.5 (PGP9.5) was decreased, and mast cell infiltration was reduced. There was a decrease in blood lymphocytes, eosinophils and basophils, a significant decrease in spleen index and a noticeable decrease in serum immunoglobulin E (Ig E). POEE significantly reduced the concentration of the skin pruritic factor interleukin (Il)-31. POAE and POEE reduced the concentration of skin histamine (His), down-regulated mRNA expression levels of interferon-γ (Ifnγ), tumor necrosis factor-α (Tnf-α), thymic stromal lymphopoietin (Tslp) and Il-4, with an increase of Filaggrin (Flg) and Loricrin (Lor) in skin lesions. These results suggested that POAE and POEE may inhibit atopic response and alleviate the clinical symptoms of AD by inhibiting the expression of immune cells, inflammatory mediators and cytokines. PO may be a potential effective drug for AD-like diseases.

The Effects of Cannabinoid Agonist, Heat Shock Protein 90 and Nitric Oxide Synthase Inhibitors on Increasing IL-13 and IL-31 Levels in Chronic Pruritus

BACKGROUND

Heat shock protein 90 (Hsp90) inhibitor and cannabinoid agonists ameliorate dry skin-induced chronic itch. We have recently reported that cannabinoids, hsp90 and nitric oxide (NO) are involved in dry skin-induced itch. Here, we investigated the contribution of the Th2 cell signaling pathway to the antipruritic effect of the hsp90 inhibitor 17-Alilamino-17-demethoxygeldanamycin (17-AAG), nitric oxide synthase (NOS) inhibitor Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) and cannabinoid agonist WIN 55,212-2 on a dry skin-induced scratch.

METHODS

Dry skin-induced chronic itching was created by topical application of AEW (acetone/diethyl ether/water). WIN 55,212-2 (1 mg/kg, i.p.), L-NAME (1 mg/kg, i.p.) and increasing doses of 17-AAG (1, 3 and 5 mg/kg,i.p.) were administered to Balb/c mice (for each group, n = 6). After these applications, skin tissues were taken from the nape region of all of the mice. Gene and protein expressions of IL-13 and IL-31 were evaluated in skin tissues by RT-PCR and immunohistochemistry, respectively.

RESULTS

IL-13 and IL-31 mRNA expressions and immune positive cell counts were increased in the AEW applied groups. WIN 55,212-2 reduced both of the increased cytokines levels, while L-NAME decreased only the IL-13. 17-AAG dose-dependently reduced the increased cytokine levels. IL-13 and IL-31 levels significantly decreased following the co-administration of these agents.

CONCLUSION

These results show that increased levels of IL-13 and IL-31 are associated with pruritus. Hsp90 inhibition and cannabinoid system activation may induce antipruritic effects through down-regulation of these cytokines.