[Qingda Granules inhibit cerebral microvascular endothelial cell apoptosis in hypertensive mice by suppressing the P53 signaling pathway].

OBJECTIVES

To investigate the mechanism by which Qingda Granules (QDG) inhibit apoptosis of hypertensive cerebral microvascular endothelial cells.

METHODS

Eighteen C57BL/6 mice were randomized into control group, angiotensin II (AngII) group, and Ang II+QDG group (n=6). The mice in the latter groups underwent subcutaneous implantation of a micropump for continuous infusion of Ang II (1000 ng·kg-1·min-1) to induce cerebral small vessel disease (CSVD) with daily gavage of saline or QDG (1.3 g/kg) for 4 weeks. Blood pressure of the mice was monitored weekly, cerebral microvascular morphology was assessed with HE staining, and the expressions of CD31, p53, cleaved caspase-3, cleaved caspase-9, Bcl-2 and Bax in the brain tissues were detected with immunohistochemistry and Western blotting. In a bEnd.3 cell model of oxygen and glucose deprivation/reoxygenation (OGD/R), the effects of QDG on cell viability and apoptosis were evaluated using CCK8 assay and Hoechst 33342 staining, respectively; the changes in mRNA expressions of P53, Bcl-2, and Bax and protein expressions of P53, Bcl-2, Bax, cleaved caspase-3 and cleaved caspase-9 were detected using RT-qPCR and Western blotting.

RESULTS

Continuous infusion of Ang II resulted in significant elevation of systolic blood pressure, diastolic blood pressure, and mean arterial pressure in the mice, causing also widening of the perivascular space of the cerebral microvasculature, reduction of CD31 and Bcl-2 expressions, and increases in the expressions of p53, Bax, cleaved caspase-3, and cleaved caspase-9. All these changes were significantly mitigated by treatment with QDG. In bEnd.3 cells, QDG treatment significantly attenuated OGD/R-induced apoptosis, increased Bcl-2 expression, and decreased expressions of P53, Bax, cleaved caspase-3, and cleaved caspase-9.

CONCLUSIONS

QDG suppress apoptosis of cerebral microvascular endothelial cells in hypertensive rats by downregulating the P53 signaling pathway to alleviate cerebral microvascular endothelial injury caused by hypertension.