Blood glucose variability can aggravate heart tissue fibrosis, possibly involving oxidative stress by inhibiting AKT signalling path.

Introduction Blood glucose fluctuation is an important factor for the development of diabetic complications. Glucose fluctuation aggravated the renal injury in diabetic nephropathy. In the present study, our aim was to investigate the effects of blood glucose fluctuation on the glomerular mesangal cells and its related mechanism. Material and methods Mesangial cells were divided into four groups: the normal glucose group (NG) cells were incubated in normal glucose conditions (5.6 mmol/l); the high glucose group (HG) cells were treated with 25 mmol/l; the glucose fluctuation (FG) group received 5.6 mmol/l and 25 mmol/l glucose repeated 3 times; the mannitol group (MG) received 5.6 mmol/l glucose plus 24.4 mmol/l mannitol as a control. Cell viability and apoptosis were detected, reactive oxygen species (ROS) level, superoxide dismutase (SOD) activity and malonaldehyde (MDA) levels were measured. Phosphorylated ser/thr protein kinase (P-AKT, phosphor-Ser473), phosphorylated glycogen synthase kinase-3β (P-GSK-3β, phosphor-Ser9) and cleaved cysteinyl aspartate-specific proteinase-3 (cleaved caspase-3) levels were assessed using western blot. Results Data suggested that mesangial cells in the FG group show higher cell viability in 12 h, and lower cell viability from 48 h. The FG group showed cell apoptosis accompanied by a significant MDA level increase and SOD activity decrease in 48 h. More importantly, glucose fluctuation could aggravate oxidative stress in glomerular mesangial cells. Furthermore, the P-AKT level was lower, and increased P-GSK-3β and cleaved caspase-3 levels were higher in the FG group than in the HG group. Conclusions Glucose fluctuation aggravates mesangial cell apoptosis, which may be partly induced by activating oxidative stress and inhibiting the AKT signaling pathway.

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It is generally accepted that inflammation plays a key role in anxiety and depression induced by diabetes. However, the underlying mechanism and effective treatment method of these diabetes-associated behavior disorders remain to be determined. In the present study, we attempted to illuminate the implication of zeaxanthin in anxiety, depression and neuroinflammation caused by hyperglycemia, and further elaborate the relevant mechanism under these neuropsychiatric disorders. In the current work, diabetic rats were induced by high glucose and fat diet followed by a single intraperitoneal injection of streptozocin, and zeaxanthin was orally administration every day (From 6th to 19th week). Diabetes-associated anxiety and depression were assessed using open field test (OFT) and Forced swimming test (FST) respectively. Moreover, the levels of interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in hippocampus were tested using ELISA and WB. Data showed that long-term zeaxanthin treatment improve diabetic symptoms and alleviate anxiety and depression in diabetic rats. Furthermore, excessive production of IL-6, IL-1β and TNF-α could be reduced with zeaxanthin treatment. In conclusion, we suggested that zeaxanthin can ameliorate diabetes-associated anxiety and depression, inhibit inflammation in diabetic rats. Our results could provide a potential therapeutic approach for the treatment of abnormal behavior induced by hyperglycemia.

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