Jiawei guomin decoction regulates the degranulation of mast cells in atopic dermatitis mice via the HIS/PAR-2 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Guomin decoction (GMD) is a traditional Chinese medicine commonly used in clinical practice. It has traditionally been used to treat all allergic diseases. Currently, Jiawei Guomin Decoction (JWGMD) is used to treat sensitive skin after initial therapy. Although it has a significant clinical therapeutic effect, the exact role of mast cell degranulation in treating atopic dermatitis (AD) is still unclear. AIM OF THE STUDY: GMD and JWGMD can both treat allergic diseases, while JWGMD focuses on skin allergies. This study aims to explore the potential effect of JWGMD on the degranulation of mast cells in an AD mouse model induced by 2,4-dinitrofluorobenzene (DNFB) and investigate the effectiveness of JWGMD in alleviating disease progression to further provide specific therapeutic targets for treating AD. MATERIALS AND METHODS: The scratching times and skin lesions of model mice induced by DNFB were observed, and skin tissues were collected for subsequent measurement. Histopathological changes in the back skin of mice were observed by haematoxylin eosin (H&E) staining, Toluidine blue staining was used to detect the degranulation of mouse skin mast cells, and the relationship between the expression of histamine (HIS), mast cell tryptase (MCT) and mast cell degranulation was analysed by enzyme-linked immunosorbent assay (ELISA). The expression of protease-activated receptor-2 (PAR-2), histamine 1 receptor (H1R), H2R, H4R and MCT proteins in AD mice was detected by Western blot (WB). Immunofluorescence assay (IFA) further confirmed the localization of PAR-2, H1R, H2R, H4R, and MCT proteins in the skin. Quantitative real-time PCR (qPCR) was used to determine PAR-2, H1R, H2R and H4R mRNA levels in skin lesions to further clarify the mechanism by which JWGMD amplifies mast cell degranulation in AD. In addition, a reliable ultrahigh-performance liquid chromatography-quadrupole electrostatic field orbitrap mass spectrometry (UPLC-QE-MS) nontargeted metabolomics analysis was performed to analyse the differences in metabolite abundance between GMD and JWGMD, and these results were used to identify the active components in JWGMD that may have antipruritic and anti-inflammatory properties and inhibit mast cell degranulation. RESULTS: After intermittent stimulation with DNFB, the skin lesions showed extensive desquamation, dryness, scabbing, skin thickening, and slight bleeding. Both treatments alleviated this phenomenon and reduced the number of scratches, with JWGMD being the most effective. JWGMD can significantly reduce inflammatory cell infiltration, oedema, and some capillary neogenesis in mice and reduce the degranulation of mast cells. The ELISA results showed that JWGMD can increase the levels of MCT and HIS proteins. The WB and IFA results demonstrated that JWGMD reduced the expression levels of PAR-2, H1R, H4R, and MCT proteins in skin lesions, with protein localization mainly in the epidermal layer, while H2R protein levels were increased and mainly localized in the dermis. In addition, JWGMD downregulates the mRNA expression of PAR-2, H1R, H2R, and H4R. Interestingly, through UPLC-QE-MS nontargeted metabolomic analysis, we detected the anti-inflammatory and antiallergy active substances in JWGMD, such as methyl eugenol, dictamnine and sinapine. CONCLUSIONS: JWGMD may alleviate itching through methyl syringol, dictamnine, sinapine and other substances, and its mechanism may be related to inhibiting the HIS/PAR-2 pathway in AD model mice and further regulating the self-amplification of mast cell degranulation. JWGMD is a potential drug for treating AD. Therefore, it deserves continuous attention and research.

Evaluación del extracto acuoso liofilizado de Boerhavia erecta L. sobre la transmisión colinérgica e histaminérgica / Evaluation of the frozen-dried aqueous extract from Boerhavia erecta L. on the cholinegic and histaminergic transmission

Se evaluó el extracto acuoso liofilizado de Boerhavia erecta L. sobre la transmisión colinérgica e histaminérgica, se emplearon cobayos Hartley para la extracción de porciones de íleon que fueron estimulados con histamina y acetilcolina con y sin la presencia del extracto, también se provocó un previo bloqueo de los receptores histaminérgicos y colinérgicos presentes en el órgano para después estimular el mismo con el extracto de B. erecta. En todos los casos se determinó la amplitud de las contracciones del órgano; los registros se realizaron mediante un transductor isotónico acoplado a un polígrafo Nihon Kodhen. El extracto acuoso liofilizado de B. erecta a concentraciones entre 0,1 mg/mL y 1 mg/mL no presentó actividad antimuscarínica y si mostró efecto antihistamínico in vitro. El extracto de B. erecta a concentraciones entre 1 y 10 mg/mL administrada de forma conjunta con acetilcolina 3x10-3 M provocó una contracción mayor que las inducidas por la B. erecta administrada de forma independiente y menor que la provocada por la acetilcolina, un comportamiento similar se obtuvo tras la administración conjunta de B. erecta e histamina 10-5 M. Cuando los receptores muscarínicos e histamínicos fueron bloqueados con atropina y difenhidramina respectivamente y posteriormente se añadió B. erecta, las contracciones provocadas por esta última fueron menores que las provocadas por el extracto sin previo bloqueo de los receptores. Estos resultados indicaron que el extracto acuoso de B. erecta. tiene tanto efecto agonista como antagonista para la histamina en dependencia de la concentración a la que se utilice y no presenta actividad antimuscarínica(AU)