目的 研究内在过表达miR-31及其下游靶基因Sfn、SuFu在咪喹莫特诱导的小鼠银屑病模型发生发展中的作用。 方法 从文献及PubMed收集与银屑病相关基因，使用Target Scan Human数据库预测miR-31靶基因。使用咪喹莫特乳膏对野生型FVB小鼠和miR-31转基因小鼠进行银屑病造模，每日采集造模小鼠背部变化图像，随后使用PASI评分评价小鼠银屑病样情况。HE染色观察组织形态学变化。取0 d、3 d、7 d模型小鼠的背部皮肤，随后进行RT-PCR检测miR-31及其下游靶基因mRNAs的表达，筛选出2个miR-31靶基因，并对筛选靶基因进行免疫荧光及Western blot检测分析。 结果 Target Scan Human数据库预测出8个miR-31下游靶基因，经荧光定量PCR筛选出2个与银屑病相关靶基因Sfn、SuFu。咪喹莫特诱导小鼠产生银屑病样症状，表现为背部出现红斑、银白鳞屑，表皮增厚等，实验结果显示miR-31实验组较野生型FVB实验组银屑病样症状轻，HE染色切片同样证实此情况。RT-PCR检测3 d、7 d时miR-31，Sfn和SuFu的表达，结果显示野生型FVB小鼠miR-31的表达均升高，而miR-31转基因小鼠miR-31的表达却降低，其靶基因Sfn、SuFu均出现相反情况，免疫荧光及western blot结果均与PCR结果一致。 结论 在银屑病动物模型中，内在过表达miR-31的皮肤，其银屑病样症状较弱，它可能联合机体内与银屑病相关的器官通过内在过表达miR-31的调控作用而减弱银屑病严重程度。Sfn、SuFu作为miR-31下游靶基因，可能在银屑病的发病过程中起抑制作用。

Objective To investigate the role of intrinsic overexpression of microRNA-31（miR-31） and its downstream target genes Stratifin （Sfn） and Suppressor of Fused（SuFu） in the development and progression of psoriasis induced by imiquimod（IMQ） in a mouse model. Methods The literature and PubMed were searched to identify the genes associated with psoriasis，and Target Scan Human database was used to predict the target genes of miR-31. IMQ cream was used to induce psoriasis in wild-type FVB mice and miR-31 transgenic mice； images of the dorsal skin were collected from these model mice daily，and the PASI score was used to evaluate the severity of psoriasis. HE staining was used to observe histomorphological changes. The dorsal skin of the mice was collected on days 0，3，and 7，and RT-PCR was used to measure the mRNA expression levels of miR-31 and its downstream target genes. Two target genes were identified and analyzed by immunofluorescence assay and Western blot. Results The Target Scan Human database predicted eight downstream target genes of miR-31，and quantitative real-time PCR obtained two target genes associated with psoriasis，i.e.，Sfn and SuFu. IMQ induced psoriasis-like symptoms in mice，including erythema，scales，and epidermal thickening of the dorsal skin. The experimental results showed that the miR-31 experimental group had milder psoriatic symptoms than the wild-type FVB experimental group，which was confirmed by HE staining. RT-PCR was used to measure the expression levels of miR-31，Sfn，and SuFu on days 3 and 7，and the results showed an increase in the expression of miR-31 in wild-type FVB mice and a reduction in miR-31 transgenic mice，while the expression levels of its target genes Sfn and SuFu showed opposite changes. The results of immunofluorescence assay and Western blot results were consistent with the results of PCR. Conclusion In the animal model of psoriasis，there are weak psoriatic symptoms in the skin with intrinsic overexpression of miR-31，and it may reduce the severity of psoriasis in combination with the organs associated with psoriasis in the body through the intrinsic overexpression of miR-31. Sfn and SuFu are the downstream target genes of miR-31 and may play an inhibitory role in the pathogenesis of psoriasis.