RESUMEN
Objective::To observe the expressions of tight junction proteins (claduin-1, claudin-7 occludin)of psoriasis-like lesions in mice, and clarify the effect of Yangxue Jiedu decoction on the epidermal barrier of psoriasis, so as to provide scientific basis for the treatment of psoriasis with Yangxue Jiedu decoction. Method::C57BL/6J mice were randomly divided into control group, model group, methotrexate group and Yangxue Jiedu decoction.Methotrexate solution and water decoction of Yangxue Jiedu decoction were prepared, and the mice were given imiquimot to induce psoriasis-skin lesions after the hair was shaved.Daily photos were taken to record the forms of skin lesions and psoriasis area and severity index(PASI) scores.Water and oil test pens were used to detect skin moisture content. The pathological changes were observed by htoxylin eosin (HE) staining, and the epidermal thickness was measured.Ki67 was detected by immunofluorescence. Immunohistochemistry was used to detect the expressions of loricrin, CD3+ T lymphocyte infiltration and claduin-1, claudin-7, occludin.In addition, the expressions of claudin-7 and occludin in skin lesions were detected by Western blot.Meanwhile, interleukin-17(IL-17) (1 mg·L-1) was used to simulate the microenvironment of psoriasis skin lesions, and the intervention was conducted by making Yangxue component, Jiedu component and Yangxue Jiedu dry powder.The toxicity of the drug on Hacat cells was detected by cell counting kit-8(CCK-8)method.The effect of the drugs on the expressions of claudin-1, claudin-7, occludin in Hacat was detected by immunofluorescence assay. Result::Yangxue Jiedu decoction could significantly reduce the psoriasis skin lesions in mice, and reduce the PASI score and skin thickness (P<0.01). Compared with the model group, the skin moisture content in the lesion was increased (P<0.01). Abnormal expressions of ki67 and loricrin in epidermis and infiltration of CD3+ T cells were reduced (P<0.01). In addition, the expressions of claudin-1, claudin-7, occludin proteins (P<0.05), and the integrity of the tight junction structure were increased.In vitro studies, compared with the model group, the expressions of claudin-1, claudin-7, and occludin in the Yangxue Jiedu group and Yangxue group were increased (P<0.05). Compared with the model group, there was no statistically significant difference in protein expression in the Jiedu group. Conclusion::By regulating the expressions of tight junction proteins between keratinocytes, Yangxue Jiedu decoction can inhibit the abnormal proliferation and differentiation, and further restore the broken epidermal barrier.Yangxue Jiedu decoction plays a role in regulating tight junction mainly through Yangxue component.