目的 探讨白术内酯I对2型糖尿病（type 2 diabetes mellitus，T2DM）大鼠胰岛细胞铁死亡的作用机制。方法 随机选取8只大鼠作为对照组，其余大鼠采用链脲佐菌素（streptozotocin，STZ，30 mg/kg）构建T2DM大鼠模型。将造模成功的大鼠随机分为模型组、卡格列净（9 mg/kg）组及白术内酯I低、高剂量（25、75 mg/kg）组，连续ig给药8周，测空腹血糖（fasting blood glucose，FBG）及口服葡萄糖耐量（oral glucose tolerance test，OGTT）；取材后测血清胰岛素（insulin，INS）、C肽（c-peptide，C-P）、谷胱甘肽（glutathione，GSH）、超氧化物歧化酶（superoxide dismutase，SOD）及胰腺组织铁含量、丙二醛（malonaldehyde，MDA）水平；采用苏木素-伊红（hematoxylin-eosin，HE）染色和透射电镜观察胰岛细胞病理学变化；免疫荧光染色观察胰岛细胞谷胱甘肽过氧化物酶4（glutathione peroxidase 4，GPX4）的表达；采用Western blotting法检测胰腺组织重链亚基溶质载体家族3成员2（solute carrier family 3 member 2，SLC3A2）、轻链亚基溶质载体家族7成员11（solute carrier family 7 member 11，SLC7A11）、谷氨酸-半胱氨酸连接酶修饰亚基（glutamate-cysteine ligase modifier subunit，GCLM）、GSH合成酶（glutathione synthetase，GSS）、GPX4、酰基辅酶A合成酶长链家族成员4（acyl coenzyme A synthetase long chain family member 4，ACSL4）蛋白表达；qRT-PCR检测胰腺组织中SLC7A11、GPX4、ACSL4 mRNA表达。结果 与对照组比较，模型组大鼠FBG、OGTT水平显著升高（P＜0.001），INS、C-P、GSH、SOD水平显著降低（P＜0.01、0.001），铁含量、MDA水平显著升高（P＜0.001）；病理和电镜结果显示胰岛细胞萎缩变形，线粒体出现大量空泡，外膜破裂，萎缩，嵴消失溶解；免疫荧光染色显示GPX4表达显著减少（P＜0.001）；SLC3A2、SLC7A11、GCLM、GSS、GPX4蛋白表达显著减少（P＜0.001），ACSL4蛋白表达显著增加（P＜0.001）；SLC7A11、GPX4 mRNA表达显著减少（P＜0.001），ACSL4 mRNA表达显著增加（P＜0.001）。与模型组比较，各给药组FBG、OGTT显著降低（P＜0.001），INS、C-P、GSH、SOD水平显著升高（P＜0.05、0.01），铁含量、MDA水平显著降低（P＜0.05、0.01、0.001）；胰腺组织病理改变表现出不同程度的减轻；免疫荧光染色显示GPX4表达显著增加（P＜0.001）；SLC3A2、SLC7A11、GCLM、GSS、GPX4蛋白表达显著增加（P＜0.05、0.01、0.001），ACSL4蛋白表达显著减少（P＜0.001）；SLC7A11、GPX4 mRNA表达显著增加（P＜0.05、0.001），ACSL4 mRNA表达显著减少（P＜0.001）。结论 白术内酯I可通过调控胱氨酸/谷氨酸反向转运系统（cystine/glutamate reverse transport system，System Xc-）/GPX4通路抑制铁死亡并发挥保护T2DM大鼠胰岛细胞的作用。

Objective To investigate the mechanism of atractylolactone Ⅰ (AT-I) on ferroptosis of pancreatic islet cells in rats with type 2 diabetes mellitus (T2DM). Methods A total of eight rats were randomly selected as the control group, and the remaining rats were treated with streptozotocin (STZ, 30 mg/kg) to construct the T2DM rat model. The modeled rats were randomly divided into model group, canagliflozin (9 mg/kg) group, AT-I low-dose (25 mg/kg) group, AT-I high-dose (75 mg/kg) group, and were administered by gavage for eight weeks, and fasting blood glucose (FBG) and oral glucose tolerance test (OGTT) were measured. The levels of serum insulin (INS), C-peptide (C-P), glutathione (GSH), superoxide dismutase (SOD), ferric content and malonaldehyde (MDA) in pancreatic tissue were measured. Hematoxylin-eosin (HE) staining and transmission electron microscopy were used to observe the pathological changes of pancreatic islet cells. Immunofluorescence staining was used to observe the expression of glutathione peroxidase 4 (GPX4) in pancreatic islet cells. Western blotting was used to detect solute carrier family 3 member 2 (SLC3A2), solute carrier family 7 member 11 (SLC7A11) and glutamate-cysteine ligase in pancreatic tissue modifier subunit (GCLM), glutathione synthetase (GSS), GPX4, acyl coenzyme A synthetase long chain family member 4 (ACSL4) protein expressions. qRT-PCR was used to detect the mRNA expressions of SLC7A11, GPX4 and ACSL4 in pancreatic tissue. Results Compared with the control group, the levels of FBG and OGTT in the model group were significantly increased (P < 0.001), INS, C-P, GSH and SOD were significantly decreased (P < 0.01, 0.001), ferric content and MDA were significantly increased (P < 0.001). Pathological and electron microscopy results showed that pancreatic islet cells atrophied and deformed, a large number of vacuoles appeared in mitochondria, the outer membrane ruptured and atrophied, and the cristae disappeared and dissolved. Immunofluorescence staining showed that the expression of GPX4 was significantly reduced (P < 0.001). Expressions of SLC3A2, SLC7A11, GCLM, GSS and GPX4 were significantly decreased (P < 0.001), and the expression of ACSL4 was significantly increased (P < 0.001). The mRNA expressions of SLC7A11 and GPX4 decreased significantly (P < 0.001), and the mRNA expression of ACSL4 was increased significantly (P < 0.001). Compared with the model group, the levels of FBG and OGTT in each administration group were significantly decreased (P < 0.001), INS, C-P, GSH and SOD were significantly increased (P < 0.05, 0.01), while ferric content and MDA were significantly decreased (P < 0.05, 0.01, 0.001). The histopathological changes of pancreas showed varying degrees of reduction. Immunofluorescence staining showed a significant increase in GPX4 expression (P < 0.001). The expressions of SLC3A2, SLC7A11, GCLM, GSS and GPX4 were significantly increased (P < 0.05, 0.01, 0.001), and the expression of ACSL4 was significantly decreased (P < 0.001). The mRNA expressions of SLC7A11 and GPX4 were significantly increased (P < 0.05, 0.001), and the mRNA expression of ACSL4 was significantly decreased (P < 0.001). Conclusion AT-I can inhibit ferroptosis by regulating the cystine/glutamate reverse transport system (System Xc-) /GPX4 pathway and play a role in protecting T2DM rat pancreatic islet cells.

R285.5

河北省自然科学基金资助项目(H2023209038);华北理工大学研究生创新项目(2024S21);科技部对发展中国家常规性科技援助项目(KY201904005);河北省创新能力提升计划项目(19392507D)