Study on optimal screening of rat model with blood stasis due to cold syndrome

OBJECTIVE To investigate the effects of freezing time on setting up a rat model of blood stasis due to cold and to provide an experimental model for the study of blood stasis due to cold syndrome with Chinese medicine.METHODS The rats were divided randomly into 5 groups， namely control group， 5-day group， 10-day group， 15-day group and 20-day group. Except those in control group， the rest rats in other groups were induced blood stasis due to cold syndrome by kept in 0 ℃ ice water lasting for 15 mins one time a day. The complete blood count indexes， ovary index， uterus index and blood rheology were carefully observed.RESULTS Compared with control group， the erythrocytes of rats in 5-day and 10-day group were dramatically reduced， the APTT dramatically extended (P<0.01). In 5-day group， plasma viscosity， blood viscosity and erythrocyte aggregation index (EAI) reduced dramatically， erythrocyte deformability improved significantly， hemoglobin decreased remarkably， and uterus index declined significantly (P<0.05~0.01).The 10-day group also showed that the percentage of neutrophils increased significantly and TT shortened remarkably (P<0.05~0.01). In 10-day and 15-day group， both of their HCT reduced obviously. HBX of 10-day group declined， while that of 15-day group increased significantly (compared with the control group， P<0.01). Besides， TT obviously shortened (P<0.05)， plasma viscosity increased significantly (P<0.01)， and APTT also tended to be short in 15-day group. When frozen time lasted for 20days， PT and APTT were prolonged significantly (P<0.01).But rectal temperature of rats in each group had no significant change during the whole modeling process (compared with control group， P>0.05).CONCLUSION Making model on the 10^th and 15^th day of modeling， coagulative function improved， and abnormal hemorheology was the most obvious in 15-day group compared with other groups. The modeling approach may provide new ideas for the research of blood stasis due to cold syndrome.