Objective: To observe the hemorrheology and tissue plasminogen activator (t-PA) changes in uterus subinvolution rats after delivery

and explore the construction of uterus subinvolution rat models and intervention mechanism of Yiqi Huayu decoction. Method: Fifty pregnant rats were randomly divided into 5 groups:normal group

model group

Xinshenghua group (5.4 g · kg-1)

and Yiqi Huayu low dose group and high-dose group (4.68

18.72 g · kg-1). Rats in all other groups except normal group received postpartum intrauterine administration of Escherichia coli to prepare inflammation postpartum uterussubinvolutionmodels.All rats were administered by intragastricinfusion with corresponding drugs during day 1-7 after the models were established. HE staining of the uterus tissues was done to observe the morphology of uterus. Blood rheometer was used to detect the hemorrheology index and double antibody sandwich method was used to detect tissue plasminogen activator (t-PA) levels. Result: Compared with the normal group

whole blood viscosity and plasma viscosity were significantly increased in model group (P<0.05) .Compared with model group

whole blood visosity and plasma viscosity were significantly decreased in Xinshenghua group and low-

high-dose Yiqi Huayu groups (P<0.05)

and the effect in Yiqi Huayu high-dose group was better than that in Xinshenghua group (P<0.05).The level of t-PA in model group was higher than that in normal group (P<0.05). Levels of t-PA were decreased in Xinshenghua group and Yiqi Huayu low and high dose groups (P<0.01)

but there was no statistically significant difference between various treatment groups. Conclusion: Postpartum uterus subinvolution rat models induced by endometritis meet the requirements of blood stasis syndrome animal models.Yiqi Huayu decoction could improve the viscous state of postpartum blood

accelerate blood circulation

and promote postpartum blood discharge.It also could reduce the high levels of t-PA

decrease the blood viscosity degree

inhibit the formation of new blood stasis

promote regeneration of blood

and help postpartum uterine involution.