Jiaotai Pill enhances insulin signaling through phosphatidylinositol 3-kinase pathway in skeletal muscle of diabetic rats / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of Jiaotai Pill (, JTP) at different constitutional proportions on insulin signaling through phosphatidylinositol 3-kinase (PI3K) pathway in the skeletal muscle of diabetic rats.</p><p><b>METHODS</b>The rat model of type 2 diabetes mellitus (T2DM) was established by intravenous injection of a small dose of streptozotoein plus high fat diet feeding. JTP at the same dosage of cinnamon and the increasing dosage of Coptis chinensis was administered to diabetic rats for nine weeks respectively. Plasma glucose and insulin levels were assayed. The expressions of proteins were determined by Western blot method.</p><p><b>RESULTS</b>All the three formulations of JTP decreased plasma glucose and fasting insulin levels as well as increased the protein expressions of insulin receptor β (InsRβ) subunit, insulin receptor substrate-1 (IRS-1), PI3K p85 subunit and glucose transporter 4 (GLUT4) in skeletal muscle. Meanwhile, JTP increased the tyrosine phosphorylation of InsRβ subunit and IRS-1, and reduced the serine phosphorylation of IRS-1 in skeletal muscle. Interestingly, the effect of JTP on improving insulin sensitivity was not dose-dependent. In contrast, JTP containing the least amount of Coptis chinensis exhibited the best effect.</p><p><b>CONCLUSION</b>JTP at different constitutional proportions attenuates the development of diabetes in a rat model of T2DM. The mechanism might be associated with enhancing insulin signaling through PI3K pathway in the skeletal muscle.</p>

Effects of jiaotai pill and its single components on ectopic fat accumulation in rats with type 2 diabetes mellitus / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the effects of Jiaotai Pill (JTP) and its single components on ectopic fat accumulation in rats with type 2 diabetes mellitus (T2DM).</p><p><b>METHODS</b>The T2DM model of rat was established by injection of streptozotocin from tail vein and high fat-caloric diet feeding. Model rats were randomly divided into the model group and four treated groups were treated respectively with JTP and its single components, Rhizoma Coptidis, Cinnamon and metformin, via gastric perfusion. Meanwhile, a normal control group was also set up. Body weight (BW), liver index (LI), levels of fasting plasma glucose (FPG), fasting serum insulin (FINS) and insulin resistance index (HOMA-IR), plasma activities of liver associated enzymes (LAE), triglyceride (TG) contents and pathological changes of liver, heart and muscle were determined before and after a 8-week treatment.</p><p><b>RESULTS</b>As compared with the normal rats, BW, LI, LAE activities, HOMA-IR, TG contents of the liver, heart and muscle were all increased in the model rats (P<0.05 or P<0.01), with pathologic appearance of fatty degeneration in different degrees. Compared with the model group, LI, LAE, HOMA-IR, and TG contents in the liver, heart and muscle tissues were decreased in different extents in the four treated groups (P<0.05 or P<0.01), and the histology of tissues in them was restored to near normal. Compared with the metformin treated group, the hepatic and muscular TG contents decreased in the JTP treated group (P<0.01), and the muscular TG content in the Rhizoma Coptidis treated group were lower (P<0.05). And the gamma-GT level in the JTP treated group was the lowest in the three Chinese drugs treated groups (P<0.01).</p><p><b>CONCLUSIONS</b>The disturbances of glucose and lipid metabolism and abnormality of liver function in T2DM rats could be improved by JTP and its single components. The mechanism might be related to their effects in improving insulin resistance and reducing ectopic fat accumulation.</p>