Abstract:Objective To investigate the effect of triptolide (TP) on hemorrheology and vascular tension in a rat model of toxicemia. Methods Male Sprague- Dawley rats were randomly divided into normal control group (NC group), toxicemia model group \[lipopolysaccharide (LPS) group\], low- dose TP group (LPS+TP- L group), middle- dose TP group (LPS+TP- M group), high- dose TP group (LPS+TP- H group), and polymyxin B group (LPS+PMX- B group). The rats were intraperitoneally injected with LPS 10 mg/kg for 6 hours to establish a model of toxicemia. The TP intervention groups were given pretreatment at 15 minutes before intraperitoneal injection of LPS. Common carotid artery intubation was performed to measure hemodynamic parameters, and the change in the tension of the thoracic aortic ring was measured. Results Compared with the NC group, the LPS group had significant reductions in heart rate, mean arterial blood pressure, left ventricular diastolic pressure, and maximal rate of the increase/decrease of left ventricular pressure (P<0.05), as well as significant reductions in the rate of contraction of the aortic ring induced by 10-8- 10-5 mol/L phenylephrine and the rate of dilation of the aortic ring induced by acetylcholine (P<0.05). Compared with the LPS group, the TP intervention groups had significant improvements in the above indices (P<0.05). The TP intervention group with endothelium- denuded aortic ring had no significant change in the systolic rate due to 10-8- 10-5 mol/L phenylephrine (P>0.05); after the treatment with L- nitro- arginine methyl ester (a non- selective nitric oxide synthase inhibitor) or methylene blue (an adenylyl cyclase inhibitor), each group had a significant improvement in contraction of the aortic ring with intact endothelium induced by phenylephrine (P<0.05). Conclusion TP can improve vascular hyporeactivity in rats with toxicemia, possibly by improving endothelial function.