Effects of Aconiti tuber polysaccharides on hypercholesterolemia and hepatic cholesterol 7α-hydroxylase expression in rats

AIM: To investigate the effects of polysaccharides isolated from Aconiti tuber (Fuzi polysaccharides,FPS) on the prevention of hypercholesterolemia induced by high-cholesterol diet and the expression of hepatic cholesterol 7α-hydroxylase (cytochrome P450 7α-1, CYP7α-1) in rats.METHODS: Fifty male Wistar rats were randomly divided into 3 groups. The rats were fed with normal diet (control group), high-cholesterol diet (HC group) or high-cholesterol diet plus FPS (224, 448 or 896 mg·kg^-1·d^-1, FPS group) for 2 weeks. The serum lipid level, body weight, food-intake and fecal amount were measured at week 2. The pathological changes of the liver were observed with HE staining. The mRNA expression of hydroxy methylglutaryl coenzyme A (HMG-CoA) reductase and CYP7α-1, the protein level of CYP7α-1, and fecal bile acid were also detected at week 2.RESULTS: FPS significantly inhibited high-cholesterol diet-induced elevation of serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) (P<0.05). HE staining showed that FPS attenuated fatty degeneration in liver. Real-time PCR analysis showed that FPS significantly up-regulated the mRNA expression of CYP7α-1, but down-regulated the mRNA expression of HMG-CoA reductase (P<0.01). The protein level of CYP7α-1 was higher in FPS group than that in HC group (P<0.01). The level of fecal bile acid in HC-treated rats was higher than that in the control rats, and FPS stimulated the excretion of fecal bile acid (P<0.05).CONCLUSION: FPS significantly reduces serum cholesterol levels, which is associated with the up-regulation of hepatic CYP7α-1 expression and down-regulation of hepatic HMG-CoA reductase expression.