Improvement and Application of Acute Blood Stasis Rat Model Aligned with the 3Rs (Reduction, Refinement and Replacement) of Humane Animal Experimentation

Objective:To establish a novel cardiocentesis method for withdrawing venous blood from the right atrium,and to improve an acute blood stasis rat model using an ice bath and epinephrine hydrochloride(Epi)while considering the 3Rs(reduction,refinement,and replacement)of humane animal experimentation.Methods:An acute blood stasis model was established in male Sprague-Dawley rats by subcutaneous injection(s.c.)Epi(1.2mg/kg)administration at 0h,followed by a 5-min exposure to an ice-bath at 2h and s.c.Epi administration at 4h.Control rats received physiological saline.Rats were fasted overnight and treated with Angelicae Sinensis Lateralis Radix(ASLR)and Pheretima the following day.Venous blood was collected using our novel cardiocentesis method and used to test whole blood viscosity(WBV),prothrombin time(PT),activated partial thromboplastin time(APTT),and fibrinogen(FIB)8ntent.Results:The rats survived the novel cardiocentesis technique;WBV value returned to normal while hematological parameters such as hemoglobin level and red blood cell count were restored to>94%of the corresponding values in normal rats following a 14-day recovery.Epi(1.2 mg/kg,s.c.)combined with a 5-min exposure to the ice bath replicated the acute blood stasis rat model and was associated with the highest WBV value.In rats showing acute blood stasis,ASLR treatment[4g/(kg-d)for 8 days]decreased WBV by 9.98%,11.09%,9.34%,9.00%,7.66%,and 7.03%(P<0.05),while Pheretima treatment[2.6g/(kg?d),for 8 days]decreased WBV by 25.49%,25.94%,16.28%,17.76%,11.07%,and 7.89%(P<0.01)at shear rates of 1,3,10,30,100,and 180 s'1,respectively.Furthermore,Pheretima treatment increased APTT significantly(P<0.01).Conclusions:We presented a stable,reproducible,and improved acute blood stasis rat model,which could be applied to screen drugs for promoting blood circulation and eliminating blood stasis.