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Abstract: FR-PO378

Increased Oxidative Stress with Reduced Renal PON2 in Type 2 Diabetic Nephropathy Mice

Session Information

Category: Diabetic Kidney Disease

  • 701 Diabetic Kidney Disease: Basic

Authors

  • Yu, Shiyue, The Core Laboratory, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
  • Chen, Xueqi, The Core Laboratory, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
  • Deng, Tianyu, The Core Laboratory, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
  • Ren, Zhiyun, The Core Laboratory, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
  • Wang, Weiwan, The Core Laboratory, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
  • Liu, Mingda, The Core Laboratory, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China
  • Wang, Xiaoyan, The Core Laboratory, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China

Group or Team Name

  • The Core Laboratory for Clinical Research.
Background

Enhanced oxidative stress with excess accumulation of reactive oxygen species (ROS) triggers progression of type2 diabetic nephropathy (T2DN). However, the effects of antioxidant enzymes including paraoxonase (PON) enzyme family in T2DN are not been studied fully. Therefore, our study was conducted to investigate the alterations in renal oxidative stress, especially antioxidant enzyme expression, in T2DN mice.

Methods

1. Mouse model: Male 6-week-old C57BL/6J mice were fed a 60% high-fat diet (HFD) for 6 weeks, and then was injected with STZ intraperitoneally at 60 mg/kg/day (T2DN, n=7) or vehicle (controls, n=5) for 3 days. Mice fed a 10% normal-fat diet (NFD) served as the background group (n=5). The mice were sacrificed at 16 weeks of HFD or NFD.
2. Cultured mouse renal proximal tubular cells (mRPTCs): the cells in low-glucose DMEM and 1%FBS were treated with 300μM sodium palmitate (PA) plus 24.5mM D-glucose or mannitol for 24h (n=4).
3. P<0.05 was considered significant for 2 group-comparison by t-test.

Results

Compared with HFD-fed mice, T2DN mice exhibited an elevated blood glucose (26.2±1.0 vs 8.7±0.6,mmol/L) together with polydipsia (13.4±1.6 vs 2.5±0.3,mL), polyphagia (4.9±0.4 vs 3.8±0.2,g), polyuria (10.6±1.5 vs 1.3±0.1,mL) and weight loss (28.2±0.7 vs 38.4±2.5,g). HOMA-IR (239.2±23.3 vs 109.5±7.8,mmol/L) and insulin tolerance test (AUC: 249±23% of control) were increased in T2DN mice with raised urine albumin-to-creatinine ratio (48.5±3.0 vs 20.8±30.7,mg/g), serum creatinine (90.7±26.6 vs 21.9±6.1,mmol/L) and urinary 8-isomeric prostaglandin (1482±86 vs 207±85,pg/mg of Cr). The staining of PAS and Masson's trichrome presented glomerular hypertrophy and collagen deposition while transmission electron microscopy revealed glomerular basement membrane thickening and podocyte fusion. Renal PON2 (66±0.03% of control) by immunoblotting was decreased while NOX1,2,4, PON1, HO1, HO2, and SODs1-3 were not affected. Except a slightly blunted response to insulin, blood glucose and renal ROS enzymes in HFD mice were not altered relative to NFD mice. PON2 was located mainly in NHE3-positive proximal tubules. Similar decrease in PON2 (73±5% of control) was also seen in cultured mRPTCs exposed to high glucose combined with PA.

Conclusion

Decreased renal PON2 may be involved in the pathogenesis of T2DN.

Funding

  • Clinical Revenue Support