Abstract: Objective To observe the effect of activating blood circulation and resolving stasis at different time points on the volume of hematoma and the degree of neurological deficit in rats with acute intracerebral hemorrhage, explore whether the adoption of this method during the acute phase increases the risk of hematoma expansion, compare the effects of medication at different timing, and to explore its mechanism of action. Methods Forty SPF-grade SD rats were randomly divided into three groups: the sham operation group, model group, experimental group. The experimental group was divided into pre-administration group, 6 h group and 24 h group according to the time of first administration. Intracerebral hemorrhage in rats was induced by injection of type Ⅶ collagenase into the caudate nucleus. Before modeling, the pre-administration group was given Naoxueshu oral liquid daily by intragastric administration for 7 consecutive days, and the other groups were given the same amount of normal saline daily. After the modeling was successful, the pre-administration group and the 6 h group were given the first dose at 6 h after the modeling, the 24 h group was given the first dose at 24 h after the modeling, and the sham operation group and the model group were given the same amount of normal saline until 72 h after the modeling. Magnetic resonance imaging was used to assess hematoma volumes 24 and 72 hours after modeling, and the behavioral neurology of rats was recorded and evaluated using the modified Neurological Deficit Score. Finally, the expression level of CD36 in rat brain tissue was determined using Western blot. Results Evaluation of hematoma volumes: Compared with 24 hours after modeling, the hematoma volumes in the pre-administration group, 6-hour group, and 24-hour group were significantly reduced at 72 hours after modeling (P<0.05). Intergroup comparison showed that the hematoma clearance rate in each experimental group was lower than that of the model group (P<0.01). Neurological deficit score: At 72 hours after modeling, the neurological deficit scores in the experimental groups were significantly lower than those in the model group (P<0.05). CD36 expression: At 72 hours after modeling, the expressions of CD36 in the pre-administration group and 6-hour group were significantly higher than that of the model group (P<0.05). Conclusion The method of activating blood and resolving stasis during the acute phase does not increase the risk of bleeding, and the effect of early medication on hematoma clearance is stronger. The mechanism of action may be related to promotion of the phagocytic function of microglia after mediation by CD36, unlike anticoagulant or antiplatelet drugs.

Key words: cerebral hemorrhage, acute, Naoxueshu oral liquid, activating blood and resolving stasis, timing of medication, rats, hematoma volume, neurological function