Deficiency of Autophagy-Related Gene 5 in Keratinocytes Leads to Aggravation of Epidermal Damage in 2,4-Dinitrochlorobenzene-Induced Allergic Contact Dermatitis

Objective:The interrelationship between apoptosis and autophagy plays an important role in many pathophysiological processes,however,whether their interplay is involved in allergic contact dermatitis(ACD)has not yet been elucidated.So,we conducted this study to determine whether keratinocyte-specific autophagy-related gene 5(ATG5)deficiency can regulate apoptosis to inhibit skin damage in mice with 2,4-dinitrochlorobenzene(DNCB)-induced ACD.Methods:This study involved keratinocyte-specificAtg5 conditional knockout(cKO)mice(Krt14cre/+-Atg5flox/flox)and control mice(Krt14+/+-Atg5flox/flox).We painted DNCB on the right ear of each mouse to induce ACD.Dermatitis scoring and measurements of ear weight and thickness were performed to evaluate inflammation levels.An immunohistochemical assay was performed to analyze immune cell infiltration.Histological study and TUNEL staining were performed to compare the differences in skin lesions betweenAtg5 cKO mice and control mice.Immunofluorescence and western blotting were used to examine the levels of ATG5 and apoptosis-related protein.The results were statistically analyzed byt test.Results:After DNCB stimulation of mice ears,we observed a more severe phenotype inAtg5 cKO mice than in control mice(dermatitis score:7.500±2.588vs.3.250±0.822,P=0.003).Further analysis of ATG5 protein confirmed keratinocyte-specific ablation ofAtg5 in cKO mice and showed that DNCB did not influence ATG5 expression.Immunohistochemistry assay revealed that the infiltrated immune cells were not involved in aggravation of the phenotype of DNCB-stimulatedAtg5 cKO mice.However,the histological study(P=0.024),TUNEL staining(P=0.024),immunofluorescence(P=0.036),and western blotting showed that the increase in keratinocyte death,especially apoptosis,contributed to aggravation of the phenotype of DNCB-stimulatedAtg5 cKO mice.Conclusion:Deficiency ofAtg5 in keratinocytes increases apoptosis,aggravating skin damage in DNCB-induced ACD mice.This has no relationship with the involvement of immune cells.

Qualitative and quantitative analysis of Arnebiae Radix and Dictamni Cortex and efficacy study of herbal extracts on allergic contact dermatitis using 3D human reconstructed epidermis

Objective:To evaluate the quality of Arnebiae Radix(AR)and Dictamni Cortex(DC)and study the efficacy of herbal extracts of these two herbs on the treatment of allergic contact dermatitis(ACD).Methods:Qualitative and quantitative analysis of effective components was performed using High Performance Thin Layer Chromatography(HPTLC),High Performance Liquid Chromatography(HPLC),and HPLC-Quadrupole Time of Flight-Mass Spectrometry(HPLC-QTOF-MS).In vitro allergic ACD 3D model was established by incubating 3D reconstructed human epidermis(RHE)with skin sensitizer,potassium dichromate.A total of 65 gene expression that were associated with ACD,which included 24 antioxidant responsive element(ARE)and 41 SENS-IS genes were quantified by q RT-PCR.More than or equal to 10 ARE genes and 18 SENN-IS genes were induced by 1.3-fold,demonstrating the successful establishment of in vitro ACD model.Oil extracts of AR and DC were applied on the in vitro ACD model to study the efficacy.Results:Batch 3 of AR and batch 2 of DC showed presence of all active ingredients with the highest concentrations.Active ingredients of the herbs were extracted using a special oil and formulated into herbal oil extracts.The herbal oil extracts were able to down regulate the induced genes in the in-vitro ACD skin model,bringing the tissue back to homeostatic status.Conclusion:The oil extracts showed the potent efficacy of using AR and DC in ACD treatment.The combination study will be done to optimize the formulation ratio which will be developed into a topical cream.

Sensitization Properties of Propolis and Balsam of Peru in Guinea Pig Maximization Test(GPMT)

Introduction: Propolis is used in Poland as an active ingredient of some drugs administered externally, dietary supplements and cosmetics. According to the literature, propolis is a non-toxic and safe substance, although it may cause allergic contact dermatitis. Aim: The aim of this study was to assess the allergenic properties of propolis and Balsam of Peru. Material and methods: The study was conducted according to the OECD Guideline for testing of chemicals-Skin sensitization with use of Guinea pig maximization test (GPMT). Guinea pigs have similar sensitivity to allergens as human body. Sensitization properties of propolis were tested in comparison with sensitization properties of Balsam of Peru because of the possibility of cross-reaction between those two substances. Results: The skin of guinea pigs in the propolis group showed no visible change compared to the control group during the first (48 h) and second observation (72 h). The skin of guinea pigs from Balsam of Peru group showed discrete erythema in only one case at the first observation (8.33% of the animals). During the second observation, no visible changes were observed compared to the control group. Conclusions: Guinea pig maximization test showed no sensitizing properties of propolis and weak sensitizing properties of Balsam of Peru in concentration of 5%.

The Effects of Nanodiamonds at the Action of Colored Metal Ions on the Skin of Guinea Pigs

The protective effect of modified nanodiamonds (MND) under the action of cobalt and nickel ions on the skin of Guinea pigs was shown. At the action of chromium ions on the skin of animals, the protective effect of MND was not found. The differences are related to different adsorption properties of MND to the investigated colored metal ions. It is shown in vitro that MND can adsorb ions of cobalt and nickel and don’t bind ions of chromium from aqueous medium. The perspectives using of MND as a new drug for the prevention allergic dermatitis caused by action of bivalent ions of metals are discussed.

Chinese Expert Consensus on Clinical Application of Patch Test (Revised 2020)

Allergic contact dermatitis is a common clinical allergic disease.The patch test is the gold standard for finding and clarifying contact allergens.With the deepening understanding of the epidemiology,pathogenesis,and clinical manifestations of contact dermatitis,as well as the increased requirements for the standardized application of patch tests,the relevant consensus needs to be continuously updated.This consensus is updated on the basis of the version issued in 2015.In this revised version,it refines the selection of clinical indications,improves the judgment end interpretation of results,adds delayed detection and patient education,and so on,which aims to further standardize clinical applications and improve the value of patch test.