Granules alleviate brain damage in spontaneously hypertensive rats by modulating the miR-124/STAT3 signaling axis.

Objectives: To explore the mechanism of Granules (QDG) for alleviating brain damage in spontaneously hypertensive rats (SHRs).

Methods: Twelve 5-week-old SHRs were randomized into SHR control group and SHR+QDG group treated with QDG by gavage at the daily dose of 0.9 g/kg for 12 weeks. The control rats, along with 6 age-matched WKY rats, were treated with saline only. Blood pressure changes of the rats were monitored, and pathologies and neuronal apoptosis in the cerebral cortex were examined with HE staining and TUNEL staining. Cerebral cortical expressions of miR-124 and STAT3 mRNA were detected using RT-qPCR, and the protein expressions of NeuN, STAT3, Bcl-2, Bax, and cleaved caspase-3 were detected with immunohistochemistry and Western blotting. In a HT22 cell model of oxygen and glucose deprivation/reoxygenation (OGD/R), the effects of QDG on cell viability and apoptosis, expressions of miR-124 and STAT3 mRNA, and protein expressions of STAT3, Bcl-2, Bax, and cleaved caspase-3 were evaluated using CCK8 assay, Hoechst 33342 staining, RT-qPCR, and Western blotting.

Results: Compared with WKY rats, SHRs had significantly elevated systolic blood pressure, diastolic blood pressure and mean arterial pressure with significantly increased neuronal apoptosis in the cerebral cortex, reduced expressions of NeuN, miR-124 and Bcl-2, and enhanced expressions of STAT3, Bax and cleaved caspase-3 (<0.05). All these changes in the SHRs were significantly ameliorated by treatment with QDG (<0.05). In the HT22 cell model, QDG treatment obviously reduced OGD/R-induced cell apoptosis, increased the expressions of miR-124 and Bcl-2, and suppressed the elevation of protein expressions of STAT3, Bax and cleaved caspase-3.

Conclusions: QDG inhibits cerebral cortical neuronal apoptosis and thereby attenuates brain damage in SHR rats by modulating the miR-124/STAT3 signaling axis.