To investigate the mechanism of effect of Huanglian Jiedu Decoction(HLJD) on vascular endothelium, we assessed the protective effect of HLJD on vascular endothelium in spontaneously hypertensive rats(SHR) and the expression of RhoA in thoracic aorta. A total of 40 SHR rats were randomly and evenly divided into model group(SHR group), positive group(captopril group), HLJD high-dose group, and HLJD low-dose group. Simultaneously, 10 Wistar Kyoto rats were used in the blank group. All groups were treated by gavage for 6 weeks. The changes of nitric oxide synthase(NOS), von Willebrand factor(vWF), endothelin(ET-1) and calmodulin(CAM) in rat serum were tested by enzyme linked immunosorbent assay(ELISA) method. The expression of RhoA at the protein and mRNA levels in thoracic aorta was determined by Western blotting(WB) and quantitative real-time PCR, respectively. Compare with the blank group after 6 weeks, the levels of ET-l and VWF in serum of the model group were significantly increased(P<0.01), and the levels of NOS and CAM were significantly decreased(P<0.01). Conversely, the levels of ET-1 and vWF in the positive and HLJD groups were significantly decreased(P<0.01 or P<0.05), and the levels of NOS and CAM were significantly increased(P<0.01 or P<0.05) compared with the model group. The expression of Rho A at the mRNA and protein levels was decreased obviously(P<0.05) in HLJD high-dose group. The results shown that HLJD increased diastolic factor(CAM and NOS) in the vascular endothelial of rats, leading to reduced contraction factor(ET-1 and vWF). HLJD revealed the preventive function in the vascular endothelial dysfunction of the early stage hypertension through adjusting secretion of blood vessel endothelium(BVE) relaxing factor and improving vascular endothelial function. The mechanism might be associated with the inhibition of the activity of RhoA protein factor.
