Qingda Granule and Its Individual Herbs Inhibit Hypertension-Induced Vascular Smooth Muscle Cells Proliferation via ERK and JNK Pathways.

objectiveTo investigate the specific role and underlying mechanisms of individual herbs in Qingda Granule (QDG) in attenuating hypertension and inhibiting proliferation of vascular smooth muscle cells (VSMCs).

methodsSpontaneously hypertensive rats (SHRs) and angiotensin II (Ang II)-stimulated VSMCs were treated with QDG or its individual herbs. SHRs were divided into groups using a completely randomized design: SHRs, valsartan (Val), QDG, Gastrodia elata Blume (Tianma, Gas), Uncaria rhynchophylla Miz. ex Havil. (Gouteng, Unc), Scutellaria baicalensis Georgi (Huangqin, Scu), and Nelumbo nucifera Gaertn (Lianzixin, Nel), 6 in each group. All treatments were administered via intragastric gavage once daily for 10 weeks. Vascular function and pathological changes were evaluated by ultrasonography and HE staining. The proliferation of VSMCs was assayed by cell counting kit-8, immunohistochemistry (IHC), and Western blot. RNA sequencing was performed to identify differentially expressed transcripts (DETs) in the abdominal aorta. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed to identify the key signaling pathways, and the expression of pathway-related proteins was subsequently verified by IHC and Western blot.

resultsQDG and its individual herb treatments significantly attenuated the increase in pulse wave velocity and aortic wall thickness in SHRs. QDG inhibited the increased PCNA expression and cell viability in VSMCs. Unc, Scu, and Nel exhibited effects similar to QDG, while Gas did not show these effects. RNA sequencing analysis identified DETs in abdominal aortic tissues. KEGG analysis based on the DETs revealed that multiple common and unique signaling pathways were enriched. Among them, the MAPK pathway was enriched in the QDG, Unc, Scu, and Nel groups, but not in the Gas group, and the cAMP pathway was significantly enriched in all groups. IHC and Western blot analysis verified that compared with the SHR group, the QDG, Unc, Scu, and Nel groups inhibited MAPK pathway activation and promoted cAMP pathway activation in the abdominal aorta of SHR and Ang II-stimulated A7R5s (P<0.05). However, Gas only inhibited the activation of the p38 MAPK pathway and promoted the activation of the cAMP pathway (P<0.05).

conclusionsThe herbs in QDG exert significant antihypertensive effects by regulating common and unique pathways. Specifically, Unc, Scu, and Nel inhibit ERK and JNK pathway activation, which likely underlies QDG's suppression of VSMCs proliferation.