Study of the mechanism of mulberry leaf alkaloids on abnormal glucose tolerance and insulin resistance in mice with gestational diabetes mellitus based on AMPK-GLUT4 axis
QIAO Yanhua1 BAI Zhangying2▲ WANG Junfang3 LI Xiaomin4 TIAN Ying5
1.Department of Health, Handan Maternal and Child Health Hospital, Hebei Province, Handan 056000, China; 2.Department of Obstetrics, Handan Maternal and Child Health Hospital, Hebei Province, Handan 056000, China; 3.Laboratory Medicine, Handan Maternal and Child Health Hospital, Hebei Province, Handan 056000, China; 4.Department of Pediatrics, Handan Maternal and Child Health Hospital, Hebei Province, Handan 056000, China; 5.Department of Obstetrics and Gynecology, Affiliated Hospital of Hebei University of Engineering, Hebei Province, Handan 056001, China
Abstract：Objective To explore the mechanism of mulberry leaf alkaloids on abnormal glucose tolerance and insulin resistance (IR) in mice with gestational diabetes mellitus (GDM) based on the AMP-activated protein kinase (AMPK)- glucose transporter 4 (GLUT4) axis. Methods Sixty SPF C57BL/6 female mice and 30 male mice with body weight of (20±3) g and age of six weeks were selected. According to the random number table method, 50 female mice in estrus were selected, after being fed a high-glycemic diet for six weeks, 25 male mice were caged overnight. After five days of fasting for 12 h, 45 female mice with successful pregnancy were injected with 35 mg/kg streptozotocin solution peritoneally to induce GDM model. After the modeling, 25% glucose was given to the stomach with 1 ml, and the 2-hour postpranpranal blood glucose (2hPBG) was measured, if 7.8 mmol/L≤2hPBG＜11.1 mmol/L, and the modeling lasted for one week, the modeling was successful. According to random number table method, 40 female mice were divided into model group, mulberry leaf alkaloids low-dose group, mulberry leaf alkaloids high-dose group, and positive drug group, with ten mice in each group; the remaining ten female mice who did not participate in modeling and had successful pregnancy were selected as control group. Mulberry leaf alkaloids low-, high-dose groups and positive drug groups were injected with 100, 200 mg/kg, and 100 mg/kg drug solution through tail vein, respectively; control group, and model group were given equal volume sterile saline. Once a day for eight weeks. Oral glucose tolerance test was performed at the 7th week of administration, and blood glucose levels were detected at 0.5, 1 h, and 2 h; the expression levels of homeostasis model assessment for insulin resistance (HOMA-IR), homeostasis model assessment-pancreatic β-cell function (HOMA-β), C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), AMPK and GLUT4 mRNA in liver tissues, and AMPK, phosphorylated adenylate protein kinase (p-AMPK), and GLUT4 protein in liver tissues of mice in all groups were compared at the 8th week of administration. Results Overall analysis showed that there were significant differences in blood glucose time, intergroup, and interaction between control group and model group (P＜0.05). Intra-group comparison: the level of blood glucose at 2 h in control group was lower than that at 0.5 and 1 h, and the differences were statistically significant (P＜0.05); the pairwise comparison of the levels of blood glucose at different time points in model group had statistical significance (P＜0.05). Comparison between groups: the levels of blood glucose at 0.5, 1 h, and 2 h in model group were higher than those in control group, and the differences were statistically significant (P＜0.05). Overall analysis showed that there were significant differences in blood glucose time, intergroup, and interaction between model group and drug administration group (P＜0.05). Intra-group comparison: the pairwise comparison of the levels of blood glucose in mulberry leaf alkaloids low-, high-dose groups at different time points showed statistical significance (P＜0.05). Comparison between groups: the levels of blood glucose in mulberry leaf alkaloids low-, high-dose groups at 0.5, 1 h, and 2 h were lower than those in model group; the levels of blood glucose at 0.5, 1 h, and 2 h in mulberry leaf alkaloids high-dose group were lower than those in mulberry leaf alkaloids low-dose group, and the differences were statistically significant (P＜0.05). HOMA-IR and the levels of CRP, TNF-α, IL-6 in model group were higher than those in control group; HOMA-β, GLUT4 mRNA， and the levels of p-AMPK and GLUT4 protein in liver tissues were lower than those in control group, and the differences were statistically significant (P＜0.05). HOMA-IR and the levels of CRP, TNF-α, IL-6 in mulberry leaf alkaloids low-, high-dose groups were lower than those in model group; HOMA-β, GLUT4 mRNA, and the levels of p-AMPK and GLUT4 protein in liver tissue weres higher than those in control group, and the differences were statistically significant (P＜0.05). HOMA-IR and the levels of CRP, TNF-α, IL-6 of mulberry leaf alkaloids high-dose group were lower than those of mulberry leaf alkaloids low-dose group; HOMA-β, GLUT4 mRNA，and the levels of p-AMPK and GLUT4 protein in liver tissues were higher than that of mulberry leaf alkaloids low-dose group, and the differences were statistically significant (P＜0.05). There were no significant differences in AMPK mRNA and protein in liver tissues among all groups (P＞0.05). Conclusion Mulberry leaf alkaloids can improve blood glucose level and inflammatory response, reduce IR and promote glucose metabolism in a dose-dependent manner in female GDM mice. The improvement may be effected by activation of the AMPK-GLUT4 axis.
乔艳华1 白章莹2▲ 王俊芳3 李晓敏4 田莹5. 基于AMPK-GLUT4轴探讨桑叶生物碱对妊娠糖尿病小鼠糖耐量异常及胰岛素抵抗的作用机制研究[J]. 中国医药导报, 2023, 20(33): 22-27.
QIAO Yanhua1 BAI Zhangying2▲ WANG Junfang3 LI Xiaomin4 TIAN Ying5. Study of the mechanism of mulberry leaf alkaloids on abnormal glucose tolerance and insulin resistance in mice with gestational diabetes mellitus based on AMPK-GLUT4 axis. 中国医药导报, 2023, 20(33): 22-27.
2023, Vol. 20 
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