RESUMEN
[Objective] To observe the effect of Baicalin on the expression of Toll-like receptors (TLRs) induced by chlamydia pneumoniae (CPN). [Methods] The endothelial cells of umbilical veins (ECV-304) was cultured in-vitro in 6-well culture plate (3 double-wells as a group). When a single layer formed, CPN or CPN + baicalin (0.48 g/L or 0.24 g/L) was added, serving as the model group and baicalin groups respectively. The wells without adding agents served as the normal group. After 5 days of culture, the intracellular growth of CPN in ECV-304 was examined by monoclonal antibody fluorescence labeling method and Giemsa stain, and the expression of TLR2 mRNA and TLR4 mRNA was detected by reverse transcriptase polymerase chain reaction (RT-PCR) in the model group. Protein expression of TLR2 on ECV-304 cell surface in the cultured supernatants was detected with flow cytometer. [Results] The intracellular growth of CPN can be found in ECV-304. The expression of TLR4 mRNA was undetectable, and high expression of TLR2 mRNA and TLR2 protein existed in ECV-304. Baicalin in high doses could lower the expression of TLR2 protein. [Conclusion] Baicalin has an inhibitory effect on the high expression of TLR2 protein in ECV-304 stimulated by CPN.