Shexiang Tongxin dropping pill improves homocysteine-induced coronary microvascular dysfunction via regulating PI3K/Akt/eNOS pathway

To establish a mouse model of homocysteine (Hcy)-induced coronary microvascular dysfunction (CMD), and to evaluate the therapeutic efficacy of Shexiang Tongxin dropping pill (STDP) and elucidate its underlying mechanisms.

The chemical composition and quality of STDP were characterized using ultra-high performance liquid chromatography, and its absorbed components were identified using ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry. CMD was induced in C57BL/6J mice by feeding a 3% methionine diet for four weeks. STDP efficacy was evaluated using laser speckle perfusion imaging, tomato lectin staining, and quantification of plasma nitric oxide (NO), reactive oxygen species (ROS), and endothelial adhesion molecules (intercellular cell adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1]). Network pharmacology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to identify potential targets and regulatory pathways. An in vitro Hcy-induced endothelial injury model was used to validate the effects of STDP on cell viability, NO production, and activation of phosphatidylinositol 3-kinase/protein kinase B/endothelial nitric oxide synthase (PI3K/Akt/eNOS) pathway.

STDP was stable, with 180 constituents identified in the preparation and 30 absorbed components in plasma. STDP treatment restored perfusion, increased plasma NO, decreased ROS, and downregulated ICAM-1 and VCAM-1. Network analysis identified 152 putative targets, highlighting the PI3K/Akt pathway as the central, with PIK3CA, AKT1, and NOS3 as key nodes. In vitro, STDP enhanced cell viability, NO production, and PI3K/Akt/eNOS phosphorylation, these effects were abolished by pharmacological inhibition of PI3K and eNOS.

A 3% methionine diet for four weeks effectively induces CMD in C57BL/6J mice. STDP, rich in bioactive components, alleviates Hcy-induced CMD by activating the PI3K/Akt/eNOS pathway, thereby improving endothelial function and microvascular perfusion. These findings support STDP as a promising therapeutic candidate for CMD management.