Inhibition of proprotein convertase subtilisin/kexin type 9: a novel mechanism of berberine and 8-hydroxy dihydroberberine against hyperlipidemia / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the effect and molecular mechanisms of different doses of 8-hydroxy dihydroberberine (Hdber) for the treatment of hyperlipidemia in rats.</p><p><b>METHODS</b>A rat model of hyperlipidemia was established by feeding rats a high-fat diet for 4 weeks in 70 rats of 80 animals, and 10 rats were randomly selected as control group. The hyperlipidemic rats were then randomly divided into the following groups: a model group (MOD); a berberine group [BBR, 156 mg/(kg day)]; Hdber groups, which were treated with different doses of Hdber [78, 39 and 19.5 mg/(kg day)]; and a simvastatin group [SIM, 4 mg/(kg day)]. The corresponding therapy was administered to the rats of each treatment via gastric tubes. Normal animals were used as a control group. The blood levels of various lipids, including total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, free fatty acid (FFA), apolipoprotein AI(Apo-AI) and apolipoprotein B (Apo-B) were examined. The protein expressions of low-density lipoprotein receptor (LDL-R), sterol regulatory element-binding protein 2 (SREBP-2), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and proprotein convertase subtilisin/kexin type 9 (PCSK-9) in liver tissues were determined by Western blot analysis.</p><p><b>RESULTS</b>Compared with the control group of rats, the model group demonstrated a deteriorated blood lipid profile and exhibited increased expression levels of PCSK-9 protein in their liver tissues (P<0.01). In addition, the high-fat diet decreased the expression levels of LDL-R, SREBP-2 and HMGCR proteins in murine liver tissues. However, the addition of berberine or Hdber reversed the blood lipid profile changes (P<0.05 or P<0.01), decreased the expression levels of PCSK-9 proteins (P<0.01), and increased the expression levels of LDL-R proteins in the hyperlipidemic rats (P<0.01). These compounds did not significantly influence the expression levels of SREBP-2 and HMGCR proteins in the hyperlipidemic rats.</p><p><b>CONCLUSIONS</b>Hdber is effective in the treatment of hyperlipidemia in rats. The therapeutic mechanisms of Hdber may be associated with increasing the expression of LDL-R protein and decreasing the expression of PCSK-9 protein in liver tissues.</p>

Effect of jiaotai pill on pancreatic fat accumulation and islet cell apoptosis in rats with type 2 diabetes / 中国中药杂志

In this study, the rat type 2 diabetes mellitus (T2DM) model was established through tail vein injection with low dose of streptozotocin (STZ) and high fat diet for 8 weeks, and then treated with Jiaotai Pill. The oral glucose tolerance test (OGTT), fasting serum insulin (FINS), free fatty acid(FFA) levels and blood lipid were assayed. HOMA-IR was calculated. Pancreatic pathology was performed. And pancreatic triglyceride (TG) content was examined by the lipid extraction method. Pancreatic islet cell apoptosis were detected by terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL). According to the results, the model group showed abnormal OGTT, increased FINS, HOMA-IR, FFA, lipid disorder, obvious fat accumulation and significantly increased TG content in pancreatic tissues, and enhanced pancreatic islet cell apoptosis. Compared with the model group, the Jiaotai Pill group displayed improved OGTT, reduced FINS, HOMA-IR, FFA, recovered lipid disorder, decreased fat accumulation and significantly declined TG content in pancreatic tissues, and lowered pancreatic islet cell apoptosis. In summary, Jiaotai pill could effectively treat type 2 diabetes in rats. Its mechanism may be related to the reduction in pancreatic fat accumulation and islet cell apoptosis.