High glucose inhibits the survival of HRMCs and its mechanism.

OBJECTIVE: High glucose can promote the apoptosis of glomerular mesangial cells and cause diabetic nephropathy (DN). However, the mechanism remains unclear. In the present study, we investigated the effects of high glucose on the survival of human renal mesangial cells (HRMCs). MATERIALS AND METHODS: Cells were treated with high glucose (30 mM) or normal glucose (5 mM) for 48 hours. Cell proliferation was determined by trypan blue assay. The relative expression of metalloproteinase-3 (TIMP3) and inflammatory factors detected by real-time polymerase chain reaction (PCR). Protein expression of Smad2/3, p-Smad2/3 and Smad7 in HRMCs were analyzed by Western blot. RESULTS: Compared with normal glucose, we found that high glucose significantly inhibited cell survival, accompanied by the decrease of tissue metalloproteinase-3 (TIMP3) mRNA expression. Western blot results showed that the expression of p-Smad2/3 was significantly up-regulated, the expression of Smad7 was significantly downregulated, and inflammatory factors IL-6/IL-8 mRNA expression were increased in the HRMCs cultured with the high glucose. We also found that, compared with the normal glucose, the level of MDA was significantly increased (p<0.01), and the level of SOD was significantly lower (p<0.05) in the HRMCs cultured with the high glucose. CONCLUSIONS: These findings suggested that high glucose inhibited the survival of HRMCs and may be associated with the downregulation of TIMP3 expression, Smad signaling pathway, inflammation and oxidative stress.

In vitro assessment of the DNA damage and senility of CD117+ stem cells collected from diabetic mice.

OBJECTIVE: Angiogenesis impairment is a common feature of diabetes mellitus (DM), whereas CD117+ bone marrow cells (BMCs) injury might be responsible for such complication. In this study, we studied the effect of hyperglycemia on the DNA damage and senility of CD117+ bone marrow cells. MATERIALS AND METHODS: We isolated CD117+ BMCs from the Streptozotocin (STZ) induced diabetes and healthy control mice. Oxidative stress was detected by flow cytometric analysis. γ-H2AX, which is the DNA damage mark, was detected by using Western blotting and immunofluorescence histochemistry. We also detected the expression of γ-H2AX and p16 by using Western blotting. RESULTS: Compared with the control mice, the level of reactive oxygen species (ROS) was increased significantly in the CD117+ BMCs collected from the diabetic mice (p<0.05), and the percentage of γ-H2AX positive cells was higher significantly (p<0.01). The expression of γ-H2AX and p16 was increased significantly in the CD117+ BMCs from the diabetic mice. CONCLUSIONS: Our experiments demonstrated the oxidative stress in CD117+ BMCs under DM conditions, while accelerating the DNA damage and senility in CD117+ BMCs as well.