Effect of Shenzhu Tiaopi granule(参术调脾颗粒) on hepatic insulin resistance in diabetic Goto-Kakizakirats via liver kinase B1/adenosine 5’-monophosphate/mammalian target of rapamycin signaling pathway

OBJECTIVE: To observe the therapeutic effect of Shenzhu Tiaopi granule(参术调脾颗粒, STG) on insulin resistance(IR) in the liver of diabetic Goto-Kakizaki(GK) rat and investigate underlying mechanisms.METHODS: Ten 12-week-old male Wistar rats were assigned as normal control(NC) group, while 4012-week-old male specific-pathogen-free GK rats were randomly divided into four experimental groups, 10 diabetic rats each. Animals were fed with a normal diet. Fasting blood glucose(FBG), water intake, and body weight were recorded during6 weeks of daily single-dose treatment: STG low-dose group, 4.5 g/kg(STG-L);STG high-dose group,9 g/kg(STG-H);metformin group, 0.1 g/kg(MET);model control(MC) and NC groups, equal volume of 0.9% Na Cl solution. The serum fasting insulin(FINS), C-Peptide and IR index(HOMA-IR) were detected every 2 weeks during treatment and glucose tolerance was measured in the 3 rd day before the material was taken. After the 6-week STG treatment, Liver tissues were processed for hematoxylin-eosin staining to perform light microscopy analysis and for assessing expression and distribution of insulin receptor substrates(IRS-1) and glucose transporter(GLUT-4) by immunohistochemistry analysis. Expression levels of liver kinase B1(LKB1)/adenosine 5’-monophosphate-activated protein kinase(AMPK)/mammalian target of rapamycin(mTOR) pathway proteins, including LKB1, phospho-AMPK(p-AMPK)/AMPK, phospho-mTOR(p-mTOR)/mTOR, and ribosomal protein S6 kinase polypeptide 1(S6 K1),were detected by Western blotting.RESULTS: STG significantly reduced the FBG level and liver fat deposition in diabetic GK rats. After STG treatment completion, FINS, HOMA-IR, C-Peptide and area under blood glucose curve(AUC)were lower in STG groups than in the MC group, indicating that IR was reduced and liver fat lesions were resolved. In liver tissues, STG groups displayed significantly higher IRS-1 and GLUT-4 expression than the MC group, along with increased LKB1 and p-AMPK/AMPK expression and decreased p-mTOR/mTOR and phospho-S6 K1 expression, suggesting that STG stimulated LKB1 activation of AMPK and suppressed themTOR/S6 K1 downstream pathway.CONCLUSION: Growing GK rats developed hepatic IR, but STG treatment significantly improved hyperglycemia and IR and resolved hepatic fatty lesions.Interestingly, STG treatment stimulated the expression of IRS-1 and GLUT-4 in the liver of diabetic GK rats, indicating a potential involvement in the regulation of the LKB1/AMPK/mTOR signaling pathway.

Clean-DM1, a Korean Polyherbal Formula, Improves High Fat Diet-Induced Diabetic Symptoms in Mice by Regulating IRS/PI3K/AKT and AMPK Expressionsin Pancreas and Liver Tissues

Objective:To investigate the effects of Clean-DM1(C-DM1),a polyherbal formulation of Radix Scrophulariae,Radix Astragali,Rhizoma Atractylodis,and Radix Salviae Miltiorrhizae,on high-fat diet(HFD)-induced diabetes mice.Methods:The information about active components of C-DM1 extract and molecular mechanism was obtained from network pharmacology analysis.Main compounds of C-DM1 extract by high performance liquid chromatography-mass spectrometry(HPLC-MS)analysis were conducted for quality control.For in vivo study,mice were induced diabetes by HFD for 12 weeks.The mice in the normal group(Nor)were maintained with a regular diet and treated with saline by gavage.The HFD model mice were randomly divided into 3 groups,including a HFD diabetic model group,a C-DM1 extract-administered group(C-DM1,500 mg/kg),and metformin-administered groups(Met,500 mg/kg),8 mice in each group.Food intake,body weight(BW),and fasting blood glucose(FBG)levels were recorded weekly for 4 weeks.After 4 weeks of treatment,alanine aminotransferase(ALT),aspartate aminotransferase(AST),blood glucose,low-density lipoprotein cholesterol(LDL-C)were determined using an automated clinical chemistry analyzer,and homeostatic model for assessing insulin resistance(HOMA-IR)levels and oral glucose tolerance test(OGTT)were detected.The histopathological changes of liver and pancreatic tissues were observed by hematoxylin-eosin staining.Insulin receptor substrate(IRS)/phosphatidylinositol 3 kinase(PI3K)/protein kinase B(AKT)and adenosine 5'-monophosphate-activated protein kinase(AMPK)expressions in liver and pancreas tissues were detected by Western blot analysis.Results:HPLC-MS identified dihydroisotanshinone,dihydroisotanshinone I,cryptotanshinone,harpagoside,and atractyloside A in C-DM1 extract.The administration of C-DM1 extract significantly decreased body weight,calorie intake,and the levels of blood glucose and insulin in the diabetic mice(P<0.05 or P<0.01).The C-DM1 extract administration improved the impaired glucose tolerance and insulin resistance in the diabetic mice and significantly decreased the levels of LDL-C,ALT and AST(P<0.01).The C-DM1 extract inhibited the histopathological changes of fatty liver and hyperplasia of pancreatic islets in the diabetic mice.The C-DM1 extract significantly increased the phosphorylation of IRS,AKT,and AMPK and the expression of PI3K in pancreas and liver tissues(P<0.05 or P<0.01),which was consistent with the analysis results of network pharmacology.Conclusion:C-DM1 extract improved diabetes symptoms in longterm HFD-induced mice by regulation of IRS/PI3K/AKT and AMPK expressions in pancreas and liver tissues,suggesting that C-DM1 formulation may help prevent the progression of T2DM.