Mechanism Exploration of TG Regulating PI3K/Akt to Improve Insulin Resistance in Liver of T2DM Rats Based on Transcriptomics / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the effect of Tangzhi pills on the improvement of insulin resistance （IR） in the liver with type 2 diabetes （T2DM） by regulating phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） signaling pathway based on differential genes and its possible molecular mechanism. MethodT2DM rat models were prepared by high fat （HFD） diet combined with streptozotocin （STZ） intraperitoneal injection. The experiment was divided into blank group， model group， metformin hydrochloride group （0.18 g·kg-1）， Tangzhi pills high （1.08 g·kg-1）， medium （0.54 g·kg-1） and low （0.27 g·kg-1） dose groups. Rat serum， liver， and pancreatic tissue were collected， and the pathological tissue of the liver and pancreas was observed using hematoxylin-eosin （HE） staining. The fasting blood glucose level （FBG） was detected， and oral glucose tolerance （OGTT） tests were conducted. Enzyme-linked immunosorbent assay （ELISA） was used to detect fasting serum insulin （FINS） and glycated hemoglobin （GHb） levels in rats. IR homeostasis model index （HOMA-IR）， β cellular homeostasis index （HOMA-β）， and insulin sensitivity index （ISI） were calculated. Biochemical methods were used to determine the levels of triglyceride （TG）， total cholesterol （TC）， low-density lipoprotein （LDL-C）， and high-density lipoprotein （HDL-C） in rat serum. Transcriptomics obtained differentially expressed mRNA from liver tissue and enriched differentially expressed pathways. Real-time reverse transcriptase polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of cyclic adenylate responsive element binding protein 3-like protein 2 antibody （CREB3l2）， B-lymphocyte tumor 2 （Bcl-2）， Toll-like receptor 2 （TLR2）， cyclin-dependent kinase inhibitor 1A （CDNK1A）， and DNA damage induced transcription factor 4-like protein （DDIT4） in liver tissue. Western blot was used to detect the protein expression of phosphorylated phosphatidylinositol 3-kinase （p-PI3K）， phosphorylated protein kinase B （p-Akt）， glucose transporter 4 （GLUT4）， insulin receptor （INSR）， and insulin receptor substrate 2 （IRS2）. ResultThe pharmacodynamic experiment results showed that compared with model group， Tangzhi pills groups repaired liver and pancreatic tissue to varying degrees， reduced blood sugar （P<0.01）， and promoted a decrease in serum FINS， GHb， and HOMA-IR （P<0.05， P<0.01）. In addition， HOMA-β and ISI increased （P<0.05， P<0.01）. The levels of TC， TG， and LDL-C decreased （P<0.05， P<0.01）， while the levels of HDL-C increased （P<0.05， P<0.01）. The transcriptomics experimental results confirmed that the PI3K/Akt signaling pathway was significantly expressed in both the blank group and model group， as well as in the high-dose Tangzhi pills group and model group. CDNK1A， DDIT4， CREB3l2， Bcl-2， and TLR2 were significantly differentially expressed mRNA during TG intervention in T2DM. Compared with the model group， the protein expression of p-PI3K， p-Akt， GLUT4， INSR， and IRS2 increased in all Tangzhi pills groups （P<0.01）. The mRNA expression of CREB3l2， Bcl-2， and TLR2 increased （P<0.01）， while that of CDNK1A and DDIT4 decreased （P<0.01）. ConclusionTangzhi pills may regulate the PI3K/Akt signaling pathway based on the differential mRNA expression of CREB3l2， Bcl-2， TLR2， CDNK1A， and DDIT4， thereby improving IR in the liver with T2DM.