Abstract: FR-PO634

Impact of P2X7 Receptor on the Progression of Diabetic Nephropathy in Rats

Session Information

Category: Diabetes

  • 501 Diabetes Mellitus and Obesity: Basic - Experimental

Authors

  • Higa, Elisa Mieko Suemitsu, Medicine Department/Unifesp, Sao Paulo, Brazil
  • Serralha, Robson Souza, Universidade Federal de São Paulo, Maua, Brazil
  • Rodrigues, Adelson, UNIFESP, Sao Paulo, Brazil
  • Punaro, Giovana, UNIFESP, Sao Paulo, Brazil
  • Mouro, Margaret G, UNIFESP, Sao Paulo, Brazil
  • Lima, Deyse, UNIFESP, Sao Paulo, Brazil
  • Farias, Camila, UNIFESP, Sao Paulo, Brazil
  • Rodrigues, Daniela B b, UNIFESP, Sao Paulo, Brazil

Group or Team Name

  • Laboratory of Nitric Oxide and Oxidative Stress
Background

Diabetes mellitus (DM) is a chronic disease which occurs when there is a failure in insulin production or when the cells become resistant to this hormone, leading to hyperglycemia. This situation results in increase of extracellular ATP concentration, which is responsible for several biological functions, among them the activation of P2X7 receptor. When rapidly activated, P2X7 allows the cations influx to the cells, mainly calcium. Constant activation of P2X7 results in opening of many non-selective pores and these in turn allow the passage of hydrophilic molecules with approximately 900 Da. In both processes, P2X7 induces cell death by necrosis via cell swelling or apoptosis, through high concentrations of calcium. Studies from our Laboratory showed that P2X7 expression and activation is associated with oxidative stress in DM. Our aim is to evaluate the effects of P2X7 on the diabetic nephropathy progression in rats.

Methods

Male Wistar rats, 7 weeks old, were unilaterally nephrectomized and DM was induced using streptozotocin (STZ, 60mg/kg, i.v.). Control rats (CTL) received citrate buffer, STZ vehicle. The animals were placed in metabolic cages in different weeks for 24-hour urine collection and a small aliquot of 3-hour blood fasting, for biochemical analysis. The renal tissue was collected after euthanasia, under anesthesia, and prepared for Western blot (WB) test against P2X7, from the 1st to 8th week of diabetes; the results were described as mean ± SEM, with significance at p<0.05.

Results

Plasma urea was significantly increased and urinary urea was significantly decreased in diabetic animals in all weeks of protocol when compared to the respective CTL. Proteinuria was increased in diabetic animals at 2nd to 8th week of protocol, when compared to the respective CTL. Analysis of P2X7 expression by qPCR and protein analysis by WB presented a significant increase of this receptor at 6th week when compared to 1st week of DM. We observed a moderate positive correlation between P2X7 protein and plasmatic urea, and a negative correlation between P2X7 and urinary urea. We found a strong positive correlation between P2X7 protein and proteinuria at 6th week (p< 0.05).

Conclusion

Our data, mainly proteinuria, suggest that P2X7 plays a role on the progression of nephropathy in this model of DM.