Abstract: Objective To investigate the effect of dissipating phlegm and blood stasis simultaneously for protecting cardiac microvascular endothelial cells (CMECs) against high glucose-induced injury and the role of AGEs/RAGE axis in the underlying mechanism. Methods The primary CMECs were isolated from rat heart by enzymatic digestion and identified by immunofluorescence assay. The CMECs exposed to 33 mmol/L glucose for 48 h were divided into model group (MC), resolving phlegm (RP) group, dissipating blood stasis (DBS) group, dissipating phlegm and blood stasis (RPDBS) group and ALT-711 group. After treatment with 10% drug-containing serum and ALT-711 for 48 h, the content of AGEs in the cells were measured with ELISA. The expressions of RAGE mRNA and protein were measured with real-time quantitative PCR, immunofluorescence assay and Western blotting; The activity of NADPH oxidase and ROS level were measured by cytochrome c reduction and fluorescent probe DHE. Results High glucose exposure significantly increased the content of AGEs, RAGE expressions at the protein and mRNA levels, NADPH oxidase activity and ROS level in the CMECs (P<0.01). These changes were significantly mitigated by treatments with RP, DBS, RPDBS and ALT-711 (P<0.01), among which RPDBS caused the most significant decrements in AGEs content, RAGE expression and NADPH oxidase activity (P<0.01, P<0.05). The reduction of ROS level in the RPDBS group was significantly greater than that in RP group (P<0.01), but similar to that in DBS group (P>0.05). Conclusion Dissipating phlegm and blood stasis simultaneously can be helpful for prevention and treatment of diabetic myocardial microangiopathy by suppressing the excessive activation of AGEs-RAGE signal axis and oxidative stress, thus protecting CMECs against high glucose-induced damage. Dissipating phlegm and blood stasis simultaneously is better than either of the therapy alone.

Key words: dissipating phlegm and blood stasis simultaneously; AGEs/RAGE axis; cardiac microvascular endothelial cells; diabetic myocardial microangiopathy; oxidative stress