ObjectiveTo investigate the possible mechanism of Pibai Yucuo Formula （枇柏愈痤方， PYF） in treating acne from the perspective of skin barrier damage. MethodsThirty-two mice were randomly divided into blank group， model group， minocycline group， and PYF group， with 8 mice in each group. Except for the blank group， mice were induced by intradermal injection of Cutibacterium acnes （C.acnes） combined with topical application of artificial sebum to establish acne model. The blank group and model group received intragastric administration of 0.2 ml of distilled water， while the PYF group received intragastric administration of 22.75 g/（kg·d）of PYF， and the minocycline group received 0.013 g/（kg·d）of minocycline suspension， all once daily for 5 consecutive days. On day 0 and day 6 of the experiment， the body weight of mice in each group was recorded， and the absolute value of the body weight difference during the experiment was calculated. Skin conditions were assessed with multifunctional skin imaging system on the 2nd， 4th and 6th day of the experiment. Skin barrier function indicators including transepidermal water loss （TEWL）， and the water content of the stratum corneum and epidermis on day 0， 2， 4 and 6 of the experiment. Optical coherence tomography （OCT） was used to observe stratum corneum and skin thickness on the 1st， 3rd and 5th day of the experiment. Hematoxylin-eosin （HE） staining was performed to observe histopathological changes， while ELISA was used to detect interleukin-17A （IL-17A） levels， and immunofluorescence staining was used to assess skin barrier-related proteins filaggrin （FLG） and loricrin （LOR） levels of skin lesions on day 6 of the experiment. ResultsCompared to the blank group， the model group showed a decrease in body weight on day 6， and an increase in the absolute value of the difference in body weight before and after the experiment （P＜0.05）. On day 4 and 6， TEWL values increased， while water content in the skin stratum corneum and epidermis decreased （P＜0.05）， accompanied by elevated IL-17A level and reduced immunofluorescence intensity of FLG and LOR proteins （P＜0.05）. The model group mice showed papules or pustules at the skin modeling site with progressively worsening desquamation under multifunctional skin imaging system. OCT revealed focal epidermal protrusions， blurred epidermal-dermal boundaries， and disorganized structural layers. HE staining showed significant epidermal hyperkeratosis and incomplete keratinization in the skin， with keratin plug formation in hair follicles and glandular lumens， thickened stratum corneum， hyperplasia of the stratum spinosum， as well as dense dermal inflammatory cell infiltration， and capillary dilation. Compared to the model group， both the minocycline group and the PYF group showed a reduced difference in body weight before and after experiment （P＜0.05）. On day 4 and 6， the TEWL value decreased， and water content of the skin stratum corneum increased （P＜0.05）； on day 6， the IL-17A level in the skin lesions decreased and immunofluorescence intensity of FLG and LOR proteins increased （P＜0.05）. On day 4 and 6， the severity of the skin lesions and range of redness and swelling were lighter than those in the model group， with reverted epidermal thickness， smoother surface and clearer epidermis-dermis boundary. HE staining showed that the degree of skin keratinization was reduced， and the inflammatory infiltration and vascular dilation in the dermis were improved compared to the model group. The PYF group showed better results than the minocycline group in reducing TEWL value on day 4 （P＜0.05）. ConclusionPYF may improve inflammation and skin barrier damage by downregulating IL-17A levels in lesion tissue and increasing skin barrier-related proteins， which could be one of the potential mechanism of action on acne.

ObjectiveTo explore the possible action mechanism of Qingshi Anti-itch Ointment （青石止痒软膏， QAO） in the treatment of psoriasis. MethodsForty mice were randomly divided into four groups， blank group， model group， calcipotriol group and QAO group， with 10 mice in each group. Except for the blank group， psoriasis was induced by applying imiquimod cream to the dorsal skin. After modeling for 6 hours daily， the calcipotriol group and QAO group were treated with 0.5 g of calcipotriol ointment or 0.5 g of QAO， respectively， applied to the treated dorsal skin. The blank group and the model group received no treatment. The skin lesions were observed， and the psoriasis area and severity index （PASI） score was assessed every other day. After 7 days， Hematoxylin and Eosin （HE） staining was performed on dorsal skin tissue to observe pathological changes. The levels of interleukin 1β （IL-1β） and interleukin 18 （IL-18） were determined by enzym-linked immunosorbent assay （ELISA）. The protein levels of Caspase-1，Pro-Caspase-1， gasdermin D （GSDMD） and gasdermin-D-N （GSDMD-N） were detected by Western Blot （WB）. The protein levels of GSDMD were observed by immunohistochemistry. ResultsCompared with the blank group， the model group mice showed redness， erythema， and white scales on their skin， with histological observations indicating epidermal thickening， elongated spines， and infiltration of inflammatory cells. The PASI scores of the skin tissue on days 1， 3， 5， and 7 were elevated； the IOD and AOD values of GSDMD protein increased； the protein levels of Caspase-1， Pro-Caspase-1，GSDMD， GSDMD-N， and IL-1β and IL-18 were significantly elevated （P＜0.05 or P＜0.01）. Compared with the model group， the QAO group and calcipotriol group showed lighter skin lesions； the PASI scores on day 5 and day 7 in the QAO group， and on day 3， 5， and 7 in the calcipotriol group， were reduced； the IOD and AOD values of GSDMD protein， and the protein level of Caspase-1， GSDMD， and GSDMD-N， as well as level of IL-18 and IL-1β decreased in both groups； in the calcipotriol group， Pro-Caspase-1 protein level also decreased （P＜0.05 or P＜0.01）. Compared with the calcipotriol group， the QAO group showed slightly redder skin， more obvious thickening of the stratum corneum， and less capillary dilation； the PASI scores on day 3 and day 7 increased， while the score on day 5 was reduced； the protein level of Pro-Caspase-1， GSDMD， GSDMD-N， and the level of IL-18 and IL-1β were increased in the QAO group （P＜0.05）. ConclusionQAO can effectively relieve psoriasis dermatitis in mice. Its potential mechanism may be related to the regulation of the Caspase-1/GSDMD protein pathway， down-regulation of IL-18 and IL-1β levels， and alleviation of pyroptosis.