Abstract: OBJECTIVE: To investigate the anti-embolic effect of Taorenchengqi Tang(TRCQT), a formulas from Traditional Chinese Medicine, plus aspirin in rats with embolic stroke induced by selective occlusion of the middle cerebral artery(MCA). Possible side effects of hemorrhagic incident and other bleeding events and anti-platelet effect were also explored.METHODS: Ninety rats were randomly separatedinto 9 groups(n = 10): group 1 a sham-operated group(n = 10); groups 2 and 3 orally treated with an isovolumetric solvent(distilled water) for 1 and3 months, followed by thromboembolic occlusion(n = 10); groups 4 and 5 orally treated with aspirin(5 mg/kg) alone for 1 and 3 months, followed by thromboembolic occlusion(n = 10); groups 6 and 7orally treated with TRCQT(0.5 g/kg) alone for 1 and3 months, followed by thromboembolic occlusion(n = 10); groups 8 and 9 orally treated with TRCQT plus aspirin for 1 and 3 months, respectively followed by thromboembolic occlusion(n = 10). The ischemic stroke in rats was induced by selective MCA occlusion. One was orally administered. After the treatments, rats' brains were removed, sectioned and stained with triphenyltetrazolium chloride(TTC) for infarct volume measurement. The incidence of subarachnoid hemorrhage(SAH) and intracerebral hemorrhage(ICH) were observed. A potential gastric bleeding side effect was assessed by measuring hemoglobin(Hb), and prothrombin time(PT). Collagen-induced platelet activation and tail vein bleeding time were measured.RESULTS: Treatment with TRCQT alone or in combination with aspirin reduced infarct volume for 1(P < 0.05), and 3(P < 0.01) months without SAH and ICH incidences, and gastric bleeding. TRCQT treatment for 1 month was also not altered PT. Moreover, a concentration dependent inhibition of collagen-induced platelet activation, followed by increasing of tail vein bleeding time was observed after TRCQT treatment.CONCLUSION: Either TRCQT alone or TRCQT plus aspirin exhibits potent neuroprotective effect by reducing infarct volume without changing the status of SAH, ICH and gastric bleeding possibly via inhib-iting the platelet activation and increasing bleeding time.

Key words: Stroke, Embolism, Aspirin, Subarachnoid hemorrhage, Cerebral hemorrhage, Prothrombin time, Blood platelet, Taorenchengqi Tang