Context: Previous studies have highlighted significant therapeutic effects of Qiqilian (QQL) capsule on hypertension in spontaneously hypertensive rats (SHRs); however, its underlying molecular mechanism remains unclear.
Obejective: We investigated the potential mechanism by which QQL improves hypertension-induced vascular endothelial dysfunction (VED).
Materials and methods: In vivo, SHRs were divided into four groups (20 per group) and were administered gradient doses of QQL (0, 0.3, 0.6, and 1.2 g/kg) for 8 weeks, while Wistar Kyoto rats were used as normal control. The vascular injury extent, IL-1β and IL-18 levels, NLRP3, ASC and caspase-1 contents were examined. In vitro, the effects of QQL-medicated serum on angiotensin II (AngII)-induced inflammatory and autophagy in human umbilical vein endothelial cells (HUVECs) were assessed.
Result: Compared with the SHR group, QQL significantly decreased thickness (125.50 to 105.45 μm) and collagen density (8.61 to 3.20%) of arterial vessels, and reduced serum IL-1β (96.25 to 46.13 pg/mL) and IL-18 (345.01 to 162.63 pg/mL) levels. The NLRP3 and ACS expression in arterial vessels were downregulated (0.21- and 0.16-fold, respectively) in the QQL-HD group compared with the SHR group. In vitro, QQL treatment restored NLRP3 and ASC expression, which was downregulated approximately 2-fold compared with that of AngII-induced HUVECs. Furthermore, QQL decreased LC3II and increased p62 contents (p < 0.05), indicating a reduction in autophagosome accumulation. These effects were inhibited by the autophagy agonist rapamycin and enhanced by the autophagy inhibitor chloroquine.
Conclusion: QQL effectively attenuated endothelial injury and inflammation by inhibiting AngII-induced excessive autophagy, which serves as a potential therapeutic strategy for hypertension.
Keywords: Hypertension; angiotensin II; autophagy; human umbilical vein endothelial cells; spontaneously hypertensive rats.