Normandie University, UNICAEN, CHU Caen, Signalisation, Electrophysiologie et Imagerie des Lésions d'Ischémie-Reperfusion Myocardique, Caen, France.
Department of Biochemistry, CHU de Caen, Caen, France.
PLoS One. 2023 Sep 21;18(9):e0289475. doi: 10.1371/journal.pone.0289475. eCollection 2023.
Glycemic variability has been suggested as a risk factor for diabetes complications but the precise deleterious mechanisms remain poorly understood. Since mitochondria are the main source of energy in heart and cardiovascular diseases remain the first cause of death in patients with diabetes, the aim of the study was to evaluate the impact of glucose swings on mitochondrial functions in the cardiomyocyte cell line HL-1.
HL-1 cells were exposed to low (LG, 2.8 mmol/l), normal (NG, 5.5 mmol/l), high (HG, 25 mmol/l) or intermittent high glucose (IHG, swing between low and high) every 2h during 12h (short-time treatment) or every 12h during 72h (long-time treatment). Anaerobic catabolism of glucose was evaluated by measuring glucose consumption and lactate production, oxidative phosphorylation was evaluated by polarography and ATP measurement, mitochondrial superoxide anions and the mitochondrial membrane potential (MMP) were analysed using fluorescent probes, and the protein oxidation was measured by oxyblot.
IHG and HG increased glucose consumption and lactate production compared to LG and NG but without any difference between short- and long-time treatments. After 72h and unlike to LG, NG and HG, we didn't observe any increase of the mitochondrial respiration in the presence of succinate upon IHG treatment. IHG, and to a lesser extent HG, promoted a time-dependent decrease of the mitochondrial membrane potential compared to LG and NG treatments. HG and IHG also increased superoxide anion production compared to LG and NG both at 12 and 72h but with a higher increase for IHG at 72h. At last, both HG and IHG stimulated protein oxidation at 72h compared to LG and NG treatments.
Our results demonstrated that exposure of HL-1 cells to glucose swings promoted time-dependent mitochondrial dysfunctions suggesting a deleterious effect of such condition in patients with diabetes that could contribute to diabetic cardiomyopathy.
血糖波动已被认为是糖尿病并发症的一个危险因素，但确切的有害机制仍知之甚少。由于线粒体是心脏的主要能量来源，而心血管疾病仍然是糖尿病患者死亡的首要原因，因此本研究的目的是评估葡萄糖波动对心肌细胞系 HL-1 中线粒体功能的影响。
HL-1 细胞在 12 小时（短期处理）或 72 小时（长期处理）内每 2 小时接受低（LG，2.8mmol/l）、正常（NG，5.5mmol/l）、高（HG，25mmol/l）或间歇性高葡萄糖（IHG，在低和高之间波动）处理。通过测量葡萄糖消耗和乳酸产生来评估葡萄糖的无氧分解代谢，通过极谱法和 ATP 测量来评估氧化磷酸化，使用荧光探针分析线粒体超氧阴离子和线粒体膜电位（MMP），并通过氧比浊法测量蛋白质氧化。
与 LG 和 NG 相比，IHG 和 HG 增加了葡萄糖消耗和乳酸产生，但短期和长期处理之间没有差异。72 小时后，与 LG、NG 和 HG 不同，我们没有观察到在 IHG 处理时存在琥珀酸的情况下线粒体呼吸的任何增加。与 LG 和 NG 处理相比，IHG 处理在 72 小时后会导致线粒体膜电位呈时间依赖性下降。HG 和 IHG 也增加了超氧阴离子的产生，与 LG 和 NG 相比，在 12 小时和 72 小时时都有所增加，但在 72 小时时 IHG 的增加幅度更大。最后，与 LG 和 NG 处理相比，HG 和 IHG 在 72 小时时均刺激了蛋白质氧化。
我们的研究结果表明，HL-1 细胞暴露于葡萄糖波动会导致线粒体功能的时间依赖性障碍，这表明这种情况在糖尿病患者中具有有害影响，可能导致糖尿病心肌病。
