OBJECTIVETo study the effect of Songling Xuemaikang Capsule (SXC) on blood pressure of spontaneously hypertensive rats (SHR) and regulatory mechanisms for peroxisome proliferator activated receptor-gamma (PPARgamma).

METHODSTotally 24 10-week-old SHR rats were randomly divided into the blank control group, the Chinese medicine (CM) group, and the Western medicine (WM) group, 8 in each group. Rats in the CM group were administered with SXC at the daily dose of 20 mg/kg by gastrogavage. Those in the WM group were administered with ramipril at the daily dose of 1 mg/kg by gastrogavage. Those in the blank control group were administered with equal volume of normal saline. The blood pressure was measured once per week. The cardiac ultrasound was performed 4 weeks later. Rats were killed and then blood was sampled from abdominal aorta. mRNA expressions of liver PPARgamma and angiotensin II type 1 receptor (AT1R) were detected by fluorescence real-time quantitative PCR. Protein expressions of PPARgamma and AT1R were detected using immunohistochemical assay (SP). The contents of PPARgamma and AT1R were quantitatively analyzed by Western blot.

RESULTSAfter 4 weeks of treatment, the blood pressure decreased in the CM group, showing statistical difference when compared with the blank control group (P < 0.01). CM was inferior to WM in lowering blood pressure. But as a whole, CM was more stable and could maintain blood pressure at a relatively stable level. The cardiac ejection fraction increased in the CM group, showing statistical difference when compared with the blank control group (P < 0.05, P < 0.01). The mRNA and protein expressions of liver PPARgamma were up-regulated in the CM group, showing statistical difference when compared with the blank control group (P < 0.05, P < 0.01). CM could obviously inhibit the AT1R mRNA expression, and down-regulate the protein expression of AT1R, showing statistical difference when compared with the blank control group and the WM group respectively (P < 0.01).

CONCLUSIONSXC decreased blood pressure and improved the cardiac ejection fraction, which might be partially achieved by up-regulating the PPARgamma mRNA expression and protein synthesis, and inhibiting the AT1R mRNA expression and AT1R protein synthesis.