Anhui University of Chinese Medicine, Hefei 230031, China.
Department of Endocrinology, the First Affiliated Hospital of Anhui University of Chinese Medicine, Hefei 230031, China.
J Tradit Chin Med. 2021 Feb;41(1):107-116. doi: 10.19852/j.cnki.jtcm.2021.01.013.
To observe the therapeutic effect of Shenzhu Tiaopi granule (, STG) on insulin resistance (IR) in the liver of diabetic Goto-Kakizaki (GK) rat and investigate underlying mechanisms.
Ten 12-week-old male Wistar rats were assigned as normal control (NC) group, while 40 12-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 during 6 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% NaCl 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 3rd 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 (S6K1),were detected by Western blotting.
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 increasedLKB1 and p-AMPK/AMPK expression and decreased p-mTOR/mTOR and phospho-S6K1expression, suggesting that STG stimulatedLKB1 activation of AMPK and suppressed them TOR/S6K1 downstream pathway.
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 theLKB1/AMPK/mTOR signaling pathway.
观察参术调脂颗粒（STG）对糖尿病 Goto-Kakizaki（GK）大鼠肝胰岛素抵抗（IR）的治疗作用，并探讨其作用机制。
将 10 只 12 周龄雄性 Wistar 大鼠设为正常对照组（NC），将 40 只 12 周龄雄性特定病原体无糖尿病 GK 大鼠随机分为 4 个实验组，每组 10 只糖尿病大鼠。动物给予普通饮食。在每日单次给药 6 周期间记录空腹血糖（FBG）、饮水量和体重：STG 低剂量组，4.5 g/kg（STG-L）；STG 高剂量组，9 g/kg（STG-H）；二甲双胍组，0.1 g/kg（MET）；模型对照组（MC）和 NC 组，给予等体积的 0.9%生理盐水。治疗期间每 2 周检测血清空腹胰岛素（FINS）、C-肽和 IR 指数（HOMA-IR），并在取材前第 3 天测量葡萄糖耐量。在 6 周的 STG 治疗后，对肝组织进行苏木精-伊红染色，进行光镜分析，并通过免疫组织化学分析评估胰岛素受体底物（IRS-1）和葡萄糖转运蛋白（GLUT-4）的表达和分布。通过 Western blot 检测肝激酶 B1（LKB1）/腺苷 5'-单磷酸激活蛋白激酶（AMPK）/哺乳动物雷帕霉素靶蛋白（mTOR）通路蛋白，包括 LKB1、磷酸化 AMPK（p-AMPK）/AMPK、磷酸化 mTOR（p-mTOR）/mTOR 和核糖体蛋白 S6 激酶多肽 1（S6K1）的表达水平。
STG 可显著降低糖尿病 GK 大鼠的 FBG 水平和肝脂肪沉积。STG 治疗完成后，STG 组的 FINS、HOMA-IR、C-肽和血糖曲线下面积（AUC）均低于 MC 组，表明 IR 降低，肝脂肪病变得到缓解。在肝组织中，STG 组 IRS-1 和 GLUT-4 的表达明显高于 MC 组，同时 LKB1 和 p-AMPK/AMPK 的表达增加，p-mTOR/mTOR 和磷酸化 S6K1 的表达减少，表明 STG 刺激 LKB1 激活 AMPK 并抑制 mTOR/S6K1 下游通路。
生长的 GK 大鼠发生肝 IR，但 STG 治疗可显著改善高血糖和 IR，并缓解肝脂肪病变。有趣的是，STG 治疗可刺激糖尿病 GK 大鼠肝内 IRS-1 和 GLUT-4 的表达，提示其可能参与调节 LKB1/AMPK/mTOR 信号通路。
