Objective: To discuss the effect and mechanism of Xuefu Zhuyu Tang on the unpredictable stimulus-induced blood stasis. Method: SPF grade rats were randomly divided into normal group

model group

Xuefu Zhuyu Tang high dose group and low dose group. Multi-factors combined stimulation method was used for 5 weeks to create blood stasis syndrome models

and at the same time

105.3

35.1 g · kg-1 Xuefu Zhuyu Tang was given by gavage. Multi-factors stimulation method was used to establish the animal models of ‘qi stagnation and blood stasis syndrome’

‘flying spot’ method was used to dynamically simulate blood flow velocity in microcirculation

laser doppler technology was used to detect blood flow volume of the tissues

coagulation method was used to detect the blood coagulation

spectrophotometric method was used to determine plasma nitric oxide (NO)

and nitric oxide synthase (NOS) activity

reverse transcription-polymerase chain reaction RT-PCR method was used to detect the expression of NOS mRNA. Result: Compared with the normal group

rate of weight gain in rats of the model group was lower than that in the normal group. Compared with the model group

Xuefu Zhuyu Tang could improve the condition of slow growth rats for body weight (P<0.05). Compared with the normal group

the arteriole and venule blood flow rates were significantly decreased in the model group

and the arteriole and venule vessel diameters were significantly contracted (P<0.05). Compared with the model group

the rats in treatment groups could significantly increase the mesenteric arteriole and venule blood flow rates

and significantly dilate the arteriole and venule vessel diameters (P<0.05)

significantly increase the blood flow volume of skin

liver

and intestine (P<0.05)

significantly reduce fibrinogen levels (P<0.05)

and significantly increase the blood flow volume of liver

intestine

stomach

ovarian and uterine (P<0.05). Compared with the normal group

NO content in plasma of rats in model group was significantly lower(P<0.01)

liver total NOS(TNOS) activity

constitutive NOS(cNOS) activity and endothelial NOS(eNOS) gene expression levels were significantly lower(P<0.01). Compared with the model group

NO levels in plasma (P<0.01)

liver TNOS activity

cNOS activity and eNOS gene expression levels were significantly higher in the treatment groups (P<0.05). Conclusion: Xuefu Zhuyu Tang can improve the symptoms of blood stasis caused by unpredictable stimulus

and its action mechanism may be associated with the gas signal molecule NO.