ABSTRACT
Objective:To observe the effect of Shuangyu Tiaozhi decoction on B-type scavenger receptor （SRB1）/cholesterol 7<italic>α</italic>-hydroxylase protein （CYP7A1）/farnesol X receptor （FXR） signaling pathway in liver of hypercholesterolemic rats， and its mechanism in reducing blood lipid. Method:Among 40 SD rats， 8 were randomly selected as normal group， and the remaining 32 were successfully established as hypercholesterolemic model， and randomly divided into 4 groups： model group， low and high-dose Shuangyu Tiaozhi decoction groups （7.8， 15.6 g·kg<sup>-1</sup>）， and simvastatin group （4 mg·kg<sup>-1</sup>）， with 8 rats in each group. The drugs were continuously given for 8 weeks. Serum total cholesterol （TC）， triglyceride （TG） and liver TC，free cholesterol （FC） and total bile acid （TBA） were measured. The pathomorphological changes in liver were observed by Hematoxylin and eosin （HE） Staining. The mRNA and protein expressions of SRB1， CYP7A1 and FXR were determined by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot. The immunohistochemistry was used to detect CYP7A1 and FXR expressions in liver. Result:Compared with the normal group， TC， TG， FC levels in the model group were significantly increased， while the TBA level was markedly decreased， the morphology showed obvious liver steatosis， and significant declines in expressions of SRB1， CYP7A1， FXR were observed by Real-time PCR， Western blot and immunohistochemistry assays （<italic>P</italic><0.05， <italic>P</italic><0.01）. Compared with the model group， the levels of TC，TG，FC in each treatment group were reduced significantly， and the TBA level was increased markedly， the liver steatosis decreased significantly， the results of Real-time PCR， Western blot and immunohistochemistry assays showed significant increase in the expressions of SRB1， CYP7A1， FXR （<italic>P</italic><0.05， <italic>P</italic><0.01）. The therapeutic effect of high-dose Shuangyu Tiaozhi decoction group was more remarkable than that in low-dose Shuangyu Tiaozhi Decoction group （<italic>P</italic><0.05）， with no obvious difference compared with simvastatin group. Conclusion:Shuangyu Tiaozhi decoction can promote hepatic RCT and synthesize bile acid by up-regulating SRB1/CYP7A1/FXR signaling pathway， so as to reduce the blood lipid levels and improve hepatic lipid metabolism of hypercholesterolemic rats.
ABSTRACT
Objective:To observe the expression of hepatocyte nuclear factor 1<italic>α</italic> （HNF1<italic>α</italic>）， proprotein convertase subtilisin/kexin type 9 （PCSK9） and low-density lipoprotein cholesterol （LDLR） in hypercholesterolemia rat liver， and investigate the mechanism of Shuangyu Tiaozhi Decoction regulating cholesterol metabolism and attenuating hypercholesterolemia. Method:After providing a high-fat diet for 4 weeks， 40 SD rats were selected， 8 of which were randomly selected as normal group and fed a normal diet， and the remaining 32 rats were fed a high-fat diet. The rats successfully established as hypercholesterolemic model， were randomized into 4 groups： model group， low dose of Shuangyu Tiaozhi decoction group （7.8 g·kg<sup>-1</sup>）， high dose of Shuangyu Tiaozhi decoction group （15.6 g·kg<sup>-1</sup>）， and simvastatin group （4 mg·kg<sup>-1</sup>）， with 8 rats in each group. The drugs were continuously given for 8 weeks. Serum total cholesterol （TC）， triglyceride （TG）， low-density lipoprotein cholesterol （LDL-C）， high-density lipoprotein cholesterol （HDL-C） were measured. The pathomorphological changes in liver were observed by hematoxylin and eosin （HE） staining. The immunohistochemistry was used to detect PCSK9 and LDLR expression in liver. The mRNA and protein expression levels of HNF1<italic>α</italic>， PCSK9 and LDLR were determined by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot. Result:Compared with normal group， the TC， TG， LDL-C levels in model group were significantly increased （<italic>P</italic><0.01）， the morphology showed obvious liver steatosis. The mRNA and protein expression of HNF1<italic>α</italic> and PCSK9 were increased （<italic>P</italic><0.05）， the mRNA and protein expression of LDLR was decreased （<italic>P</italic><0.05）. Compared with model group， the serum TC， TG， LDL-C levels were significantly lowered in the Shuangyu Tiaozhi decoction high-dose group （<italic>P</italic><0.01）， the serum TC， LDL-C levels were significantly lowered in the Shuangyu Tiaozhi decoction low-dose group and simvastatin group （<italic>P</italic><0.05，<italic>P</italic><0.01）， while no significant effect was observed on the serum HDL-C levels in each treatment group. The liver steatosis decreased in each treatment group. The mRNA and protein expression of HNF1<italic>α</italic> was obviously decreased in each treatment group （<italic>P</italic><0.05，<italic>P</italic><0.01）， the mRNA and protein expression of PCSK9 was obviously decreased in Shuangyu Tiaozhi decoction low and high-dose groups （<italic>P</italic><0.05，<italic>P</italic><0.01）， the mRNA expression of PCSK9 was significantly increased in the simvastatin group （<italic>P</italic><0.01）， while the protein expression showed a downward trend. The LDLR mRNA levels were significantly increased in each treatment group （<italic>P</italic><0.01）， the LDLR protein expression was significantly increased in Shuangyu Tiaozhi high-dose group （<italic>P</italic><0.01）， and showed an upward trend in Shuangyu Tiaozhi low-dose group and simvastatin group. Results of immunohistochemistry showed PCSK9 expression was weakly positive， the expression of LDLR was strongly positive in each treatment group. The therapeutic effect of Shuangyu Tiaozhi decoction high-dose group was more remarkable than simvastatin group， while there was no obvious difference between the Shuangyu Tiaozhi decoction low-dose group and simvastatin group. Conclusion:Shuangyu Tiaozhi decoction may reduce the blood lipid levels through HNF1<italic>α</italic>/PCSK9/LDLR signaling pathway， play an active role on regulating cholesterol metabolism and alleviating high-fat diet-induced hypercholesterolemia.
ABSTRACT
Objective:To observe the expression levels of niemann-pick C1-like 1 (NPC1L1) and adenosine triphosphate-binding cassette transporters G8 (ABCG8) in intestine of hyperlipidemic model rats, in order to investigate the therapeutic mechanism of Shuangyu Tiaozhi decoction on hyperlipidemia. Method:A total of 40 SD rats were selected, including 8 for normal control group. The remaining 32 rats were used to establish hyperlipemic model. After modeling, the rats were randomly divided into the model group (equivalent normal saline), the high and low-dose Shuangyu Tiaozhi groups (15.6, 7.8 g·kg-1), and the Simvastatin group (4 mg·kg-1), with 8 in each group. They were given drugs by gavage for 8 weeks. The levels of total cholesterol (TC), triglyceride (TG) in serum and total cholesterol (TTC), free cholesterol (FTC) in liver of rats in each group were determined by biochemical and enzymatic methods. The morphological changes of liver were observed by hematoxylin-eosin (HE) staining, and the levels of expressions of NPC1L1, ABCG8 and liver X receptor-α (LXR-α) in intestine were detected by Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR) and Western blot. The expression of ABCG8 protein was determined by immunohistochemistry. Result:After successful replication of the hyperlipidemia model, the blood lipid level was abnormally increased, and the liver steatosis became obvious in the model group compared with the normal control group. The expression levels of NPC1L1, LXR-α and ABCG8 increased significantly (PPα were significantly down-regulated, but ABCG8 was obviously up-regulated in a dose-dependent manner (PPPPPPConclusion:Shuangyu Tiaozhi decoction can reduce the blood lipid level of hyperlipemic rat model by reducing the absorption of cholesterol. Its mechanism may be correlated with the down-regulation of NPC1L1 expression and the up-regulation of ABCG8 expression.