Hyperglycaemia, a key metabolic abnormality in diabetes mellitus, is implicated in pathological cardiogenesis during embryological development. However, the underlying mechanisms and potential therapeutic targets remain unknown. We, therefore, studied the effect of hyperglycaemia on mouse embryonic stem cell (mESC) cardiac differentiation. The mESCs were differentiated via embryoid body (EB) formation and cultured under conditions with baseline (25 mM) or high (50 mM) glucose. Time-lapse microscopy images of pulsatile mESCs and Ca²⁺ transients were recorded. Biomarkers of cellular changes were detected using immunocytochemistry, terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assay, and Western blot analyses. Differentiated, spontaneously beating mESCs stained positive for cardiac troponin T, α-actinin 2, myosin heavy chain, and connexin 43. Hyperglycaemia decreased the EB diameter and number of beating EBs as well as the cellular amplitude of contraction, the Ca²⁺ transient, and the contractile response to caffeine (1 mM), but had no effect on the expression of the sarco-endoplasmic reticulum calcium transport ATPase 2 (SERCA 2). Furthermore, hyperglycaemia decreased the expression of B cell lymphoma 2 (Bcl-2) and increased the expression of cytoplasmic cytochrome c and the number of TUNEL-positive cells, but had no effect on the expression of one of the mitochondrial fusion regulatory proteins, optic atrophy protein 1 (OPA1). Overall, hyperglycaemia suppressed the mESC cardiomyocyte-like differentiation and induced contractile dysfunction. The results are consistent with mechanisms involving abnormal Ca²⁺ handling and mitochondrial-dependent apoptosis, factors which represent potential therapeutic targets in developmental diabetic cardiac disease.

高血糖症是糖尿病的关键代谢异常，与胚胎发育过程中的病理性心脏发生有关。然而，潜在的机制和潜在的治疗靶点仍然未知。因此，我们研究了高血糖对小鼠胚胎干细胞 (mESC) 心脏分化的影响。mESCs 通过胚状体 (EB) 形成进行分化，并在基线 (25 mM) 或高 (50 mM) 葡萄糖的条件下培养。^{脉动 mESCs 和 Ca 2+}的延时显微镜图像瞬态被记录下来。使用免疫细胞化学、末端脱氧核苷酸转移酶 dUTP 缺口末端标记 (TUNEL) 测定和蛋白质印迹分析检测细胞变化的生物标志物。分化的、自发跳动的 mESCs 对心肌肌钙蛋白 T、α-肌动蛋白 2、肌球蛋白重链和连接蛋白 43 染色呈阳性。高血糖会降低 EB 直径和跳动 EB 的数量以及细胞收缩幅度、Ca ²⁺瞬时和对咖啡因 (1 mM) 的收缩反应，但对肌内质网钙转运 ATPase 2 (SERCA 2) 的表达没有影响。此外，高血糖降低了 B 细胞淋巴瘤 2 (Bcl-2) 的表达，增加了细胞质细胞色素 c 的表达和 TUNEL 阳性细胞的数量，但对线粒体融合调节蛋白之一的表达没有影响，光学萎缩蛋白 1 (OPA1)。总体而言，高血糖抑制了 mESC 心肌细胞样分化并诱导了收缩功能障碍。结果与涉及异常Ca ²⁺处理和线粒体依赖性细胞凋亡的机制一致，这些因素代表了发育性糖尿病心脏病的潜在治疗靶点。