Abstract: BACKGROUND: Buqi Huoxue Compounds have shown significant clinical effects on the treatment of ischemic stroke due to qi deficiency and phlegm stasis, but its specific mechanism of action needs to be further clarified.
OBJECTIVE: To observe the effects of Buqi Huoxue Compounds on the neurological function, p-Akt and serum exosome expression in a rat model of cerebral ischemia-reperfusion injury. 
METHODS: Forty adult male SPF Sprague-Dawley rats, 6 weeks old, were randomly divided into sham operation group, model group, Buqi Huoxue Compounds group, Buqi Huoxue Compounds+GW4869 group, with 10 rats in each group. In the latter three groups, a rat model of cerebral ischemia-reperfusion injury was established using thread technique. The sham operation group was given incision and separation without inserting a suture. The Buqi Huoxue Compounds group was intragastrically given Buqi Huoxue Compounds (6.49 g/kg, administered three times a day) 2 hours after reperfusion; the GW4869+Buqi Huoxue Compounds group was intragastrically given Buqi Huoxue Compounds (6.49 g/kg, administered three times a day) 2 hours after reperfusion and intraperitoneally given GW4869 [2.5 mg/(kg•d)] 2 hours before gavage with 3 days after modeling. Both the sham operation group and model group received equal amounts of saline via gavage, three times a day, for 7 consecutive days. Neurological function, cerebral infarct volume, brain tissue morphology, characterization of serum exosome, p-Akt in the cortical area and CD63 and TSG101 in serum exosome were detected after 7 days of administration.
RESULTS AND CONCLUSION: (1) After modeling, compared with the sham operation group, the neurological function scores of the model group, Buqi Huoxue Compounds group, and Buqi Huoxue Compounds+GW4869 group were significantly increased (P < 0.01 or P < 0.05). After 7 days of intervention, the neurological function scores of the Buqi Huoxue Compounds group were significantly lower than those of the model group and Buqi Huoxue Compounds+ GW4869 group (all P < 0.01). (2) The results of 2,3,5-triphenyltetrazolium chloride staining showed that cerebral infarct foci were observed in the model group, Buqi Huoxue Compounds group, and Buqi Huoxue Compounds+GW4869 group, and the cerebral infarct volume in the Buqi Huoxue Compounds group was smaller than that in the model group and the Buqi Huoxue Compounds+GW4869 group (P < 0.01). (3) The results of hematoxylin-eosin staining showed that the morphological and structural abnormalities of nerve cells in the Buqi Huoxue Compounds group and Buqi Huoxue Compounds+GW4869 group were less severe than those in the model group, but some cells still exhibited cytoplasmic agglutination and pyknosis in the Buqi Huoxue Compounds group and Buqi Huoxue Compounds+GW4869 group. (4) NanoSight analysis showed that the diameters of the isolated particles ranged from 60 nm to 300 nm, consistent with the characteristic size of exosomes. (5) Western blot results showed that the expression of p-Akt in the infarct zone and expression of CD63 and TSG101 in serum exosomes were significantly lower in the model group compared with the sham operation group (P < 0.05 or P < 0.01). Compared with the model group, the expression of p-Akt in the infarct zone and expression of CD63 and TSG101 in serum exosomes were significantly higher in the Buqi Huoxue Compounds group than in the model group (P < 0.05 or P < 0.01). However, the p-Akt expression in the infarct zone and CD63 expression in serum exosomes decreased significantly in the Buqi Huoxue Compounds+GW4869 group (P < 0.05), while TSG101 expression decreased without significant difference after the addition of GW4869. (6) To conclude, Buqi Huoxue Compounds attenuate cerebral ischemia-reperfusion injury and increase the expression of p-Akt in rats by promoting exosome secretion.

Key words: Buqi Huoxue Compounds, ischemia-reperfusion, neurological function, p-Akt, exosome, engineered tissue construction