RESUMEN
OBJECTIVE:To explore the mec hanism of baicalein plat elet aggregation inhibitiory effect and lung tissue protective effect of baicalein in model rats with acute pulmonary embolism. METHODS :Totally 36 rats were randomly divided into normal control group (n=6)and modeling group (n=30). The acute pulmonary embolism model was established by autologous thrombus replication in modeling group ,and the sham operation of rats in normal control group was carried out. After modeling , 30 model rats were randomly divided into model control group ,positive drug group (low molecular weight heparin calcium 0.01 mL/kg,subcutaneous injection ),baicalein low-dose ,middle-dose and high-dose groups (25,50,100 mg/kg,intraperitoneal injection),with 6 rats in each group. Normal control group and model control group were intraperitoneally injected constant volume of normal saline ;administration groups were given relevant medicine ,once a day ,for consecutive 7 d. After medication , platelet aggregation rates of rats after activated with adenosine diphosphate (ADP) and arachidonic acid (AA) and platelet activation index (RPI)were detected ;lung histopathology was observed by HE staining ;serum platelet activation markers granule membrane(CD62P)and lysosomal membrane glycoprotein (CD63),growth differentiation factor- 15(GDF-15)and N-terminal B-type natriuretic peptide (NT-proBNP)were measured by ELISA. The mRNA expression levels of Notch 2,Notch3 and Notch signaling ligand PLL 1,JAG2 were detected by RT-PCR method. The protein expression levels of Notch 2,Notch3,DLL1 and JAG2 in lung tissue were detected by immunohistochemistry and Western blotting assay. RESULTS :Compared with normal control group,plasma ADP-activated platelet aggregation rate ,AA-activated platelet aggregation rate ,RPI,serum levels of CD 62P, CD63,GDF-15 and NT-proBNP were increased significantly (P<0.05). The lung tissue of rats was in a state of severe inflammatory infiltration. mRNA and protein expression levels of Notch 2,Notch3,DLL1 and JAG 2 in lung tissue decreased significantly(P<0.05). Compared with model control group ,changes of above indexes of rats were improved significantly in baicalein groups (P<0.05). CONCLUSIONS :Baicalein can reduce platelet aggregation and improve the pathological state of lung tissue in rats with acute pulmonary embolism. Its mechanism 0270) may be related to activating Notch signal pathway.