Abstract: Objective: To determine the effect of Xiaoyinjiedu Decoction on the proliferation of keratinocytes through the cell division cycle protein 7 (cdc7) in the mouse model of psoriasis. Methods: Twenty healthy male BALB/c mice were randomly divided into the control group, psoriasis model group, Xiaoyinjiedu Decoction group and cdc7 inhibitor TAK-931 group with 5 mice in each group. In addition to the control group, imiquimod was applied to the back of the mice for 5 days in other groups to induce psoriasis model. The mice in the control group and psoriasis model group were treated with distilled water 10 mL/kg, twice a day, for 5 days. The mice in the Xiaoyinjiedu Decoction group and cdc7 inhibitor TAK-931 group were treated with Xiaoyinjiedu Decoction 23.4 g/kg and cdc7 inhibitor TAK-931 2 mg/kg twice a day, for 5 days. The PASI scores were assessed. The morphological changes of lesions and the thickness of the epidermis were measured by HE staining. The level of cdc7 in epidermis of skin lesion was assessed by immunohistochemistry. Results: The mouse psoriasis model was constructed successfully. Compared to the psoriasis model group, the PASI scores of lesions in the Xiaoyinjiedu Decoction group and TAK-931 group were lower, the hyperplasias were milder, the inflammatory cells were less (Ps<0.05). The level of positive cells of cdc7 in epidermis in the Xiaoyinjiedu Decoction group was significantly lower than that in the psoriasis model group (P<0.05). Conclusion: Xiaoyinjiedu Decoction can inhibit the excessive proliferation of keratinocytes, which may through down-regulating the expression of cdc7.

Key words: Xiaoyinjiedu Decoction, cell division cycle protein 7, psoriasis