Diabetes mellitus (DM) is a disease syndrome characterized by chronic hyperglycaemia. A long-term high-glucose environment leads to reactive oxygen species (ROS) production and nuclear DNA damage. Human umbilical cord mesenchymal stem cell (HUcMSC) infusion induces significant antidiabetic effects in type 2 diabetes mellitus (T2DM) rats. Insulin-like growth factor 1 (IGF1) receptor (IGF1R) is important in promoting glucose metabolism in diabetes; however, the mechanism by which HUcMSC can treat diabetes through IGF1R and DNA damage repair remains unclear. In this study, a DM rat model was induced with high-fat diet feeding and streptozotocin (STZ) administration and rats were infused four times with HUcMSC. Blood glucose, interleukin-6 (IL-6), IL-10, glomerular basement membrane, and renal function were examined. Proteins that interacted with IGF1R were determined through coimmunoprecipitation assays. The expression of IGF1R, phosphorylated checkpoint kinase 2 (p-CHK2), and phosphorylated protein 53 (p-p53) was examined using immunohistochemistry (IHC) and western blot analysis. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of 8-hydroxydeoxyguanosine (8-OHdG). Flow cytometry experiments were used to detect the surface markers of HUcMSC. The identification of the morphology and phenotype of HUcMSC was performed by way of oil red "O" staining and Alizarin red staining. DM rats exhibited abnormal blood glucose and IL-6/10 levels and renal function changes in the glomerular basement membrane, increased the expression of IGF1 and IGF1R. IGF1R interacted with CHK2, and the expression of p-CHK2 was significantly decreased in IGF1R-knockdown cells. When cisplatin was used to induce DNA damage, the expression of p-CHK2 was higher than that in the IGF1R-knockdown group without cisplatin treatment. HUcMSC infusion ameliorated abnormalities and preserved kidney structure and function in DM rats. The expression of IGF1, IGF1R, p-CHK2, and p-p53, and the level of 8-OHdG in the DM group increased significantly compared with those in the control group, and decreased after HUcMSC treatment. Our results suggested that IGF1R could interact with CHK2 and mediate DNA damage. HUcMSC infusion protected against kidney injury in DM rats. The underlying mechanisms may include HUcMSC-mediated enhancement of diabetes treatment via the IGF1R-CHK2-p53 signalling pathway.
糖尿病是一种以慢性高血糖为特征的疾病综合征，长期的高糖环境会导致活性氧（ROS）的产生和核DNA损伤。人脐带来源的间充质干细胞（HUcMSC）输注2型糖尿病（T2DM）大鼠后可诱导显著的抗糖尿病作用。胰岛素样生长因子1受体（IGF1R）在促进糖尿病患者的葡萄糖代谢中起着重要作用；然而，HUcMSC通过IGF1R和DNA损伤修复治疗糖尿病的机制尚不清楚。本研究经高脂饮食喂养和链脲佐菌素（STZ）给药诱导建立糖尿病大鼠模型，并给大鼠输注四次HUcMSC，随后检测血糖、白细胞介素-6（IL-6）、IL-10、肾小球基底膜和肾功能。通过共免疫沉淀测定与IGF1R相互作用的蛋白质；使用免疫组织化学（IHC）和蛋白质印迹分析检测IGF1R、磷酸检查点激酶2（p-CHK2）和p-p53的表达；采用酶联免疫吸附试验（ELISA）测定血清8-羟基脱氧鸟苷（8-OHdG）的水平；使用流式细胞术检测HUcMSC的表面标志物；采用油红O染色和茜素红染色鉴定HUcMSC的形态和表型。结果显示：糖尿病大鼠肾小球基底膜、血糖、IL-6/10水平和肾功能异常；胰岛素样生长因子1（IGF1）和IGF1R表达增加；IGF1R与CHK2相互作用；p-CHK2在IGF1R敲低细胞中的表达显著降低。当使用顺铂诱导DNA损伤时，p-CHK2的表达高于未经顺铂诱导的IGF1R敲低组。HUcMSC的输注改善了糖尿病大鼠的血糖异常，并保护了其肾脏结构和功能。糖尿病组IGF1、IGF1R、p-CHK2和p-p53的表达以及8-OHdG的水平与对照组相比显著增加，且在HUcMSC治疗后降低。综上所述，IGF1R可以与CHK2相互作用并介导DNA损伤，且HUcMSC对糖尿病大鼠肾损伤有保护作用。HUcMSC通过介导IGF1R-CHK2-p53信号通路是治疗糖尿病的潜在机制。.
糖尿病是一种以慢性高血糖为特征的疾病综合征，长期的高糖环境会导致活性氧（ROS）的产生和核DNA损伤。人脐带来源的间充质干细胞（HUcMSC）输注2型糖尿病（T2DM）大鼠后可诱导显著的抗糖尿病作用。胰岛素样生长因子1受体（IGF1R）在促进糖尿病患者的葡萄糖代谢中起着重要作用；然而，HUcMSC通过IGF1R和DNA损伤修复治疗糖尿病的机制尚不清楚。本研究经高脂饮食喂养和链脲佐菌素（STZ）给药诱导建立糖尿病大鼠模型，并给大鼠输注四次HUcMSC，随后检测血糖、白细胞介素-6（IL-6）、IL-10、肾小球基底膜和肾功能。通过共免疫沉淀测定与IGF1R相互作用的蛋白质；使用免疫组织化学（IHC）和蛋白质印迹分析检测IGF1R、磷酸检查点激酶2（p-CHK2）和p-p53的表达；采用酶联免疫吸附试验（ELISA）测定血清8-羟基脱氧鸟苷（8-OHdG）的水平；使用流式细胞术检测HUcMSC的表面标志物；采用油红O染色和茜素红染色鉴定HUcMSC的形态和表型。结果显示：糖尿病大鼠肾小球基底膜、血糖、IL-6/10水平和肾功能异常；胰岛素样生长因子1（IGF1）和IGF1R表达增加；IGF1R与CHK2相互作用；p-CHK2在IGF1R敲低细胞中的表达显著降低。当使用顺铂诱导DNA损伤时，p-CHK2的表达高于未经顺铂诱导的IGF1R敲低组。HUcMSC的输注改善了糖尿病大鼠的血糖异常，并保护了其肾脏结构和功能。糖尿病组IGF1、IGF1R、p-CHK2和p-p53的表达以及8-OHdG的水平与对照组相比显著增加，且在HUcMSC治疗后降低。综上所述，IGF1R可以与CHK2相互作用并介导DNA损伤，且HUcMSC对糖尿病大鼠肾损伤有保护作用。HUcMSC通过介导IGF1R-CHK2-p53信号通路是治疗糖尿病的潜在机制。
Keywords: Checkpoint kinase 2 (CHK2); DNA damage repair; Diabetes mellitus; Human umbilical cord mesenchymal stem cell (HUcMSC); Insulin-like growth factor 1 receptor (IGF1R); Protein 53 (p53).