Objective: To study the effects of Zuogui Wan on the mRNA expression of 11 β-hydroxysteroid dehydrogenase type 1(11 β-HSD1) in placenta of gestational diabetes mellitus (GDM) rats. Method: Pregnant reproduction age SD rats were randomly divided into 5 groups:the normal pregnancy (C) group

the GDM control (GDM) group

the diabetes insulin treated (INS) group

Zuogui Wan treated (ZGW) group and Zuogui Wan combined insulin treated (F) group. The GDM was induced except the C group by injecting streptozocin (STZ) abdominally at 45 mg·kg-1. The rats in the three treated groups received the treatment of Zuogui Wan and/or insulin from injecting STZ until 19-day pregnant. Glycemia was detected by using the glucose oxidase method. The corticosterone and insulin in blood serum were detected by using ELISA kit. The mRNA expression level of 11 β-HSD1 in placenta was evaluated by RT-qPCR

and the quantitative analysis was conducted. Result: Compared with the C group

the glycemia

serum insulin

corticosterone level and placental 11 β-HSD1 mRNA expression level increased in the GDM group (P <0.01). Compared with the GDM group

the glycemia level

serum insulin

corticosterone level and placental 11 β-HSD1 mRNA expression level decreased significantly in AGW and F groups

but the results were higher than those in the C group. Moreover

the effect is better in F group. Conclusion: Zuogui Wan could reduce the level of glycemia in diabetic rats. The mRNA expression of 11 β-HSD1 was found in placental and could be influenced by GDM. Zuogui Wans have the improving effects on the glycemic status of GDM rats

which may be related to reducing the placental 11 β-HSD1 gene expression level.