Esculin reduces P2X7 and reverses mitochondrial dysfunction in the renal cortex of diabetic rats

AIMS

To evaluate the effects of esculin treatment on P2X7 receptor and mitochondrial dysfunction in the renal cortex of diabetic rats.

MAIN METHODS

Male Wistar rats, 7 weeks old, were unilaterally nephrectomized. Part of these animals were induced to diabetes using streptozotocin (60 mg/kg). Diabetes was confirmed 48 h after induction, with blood glucose levels ≥200 mg/dL. Part of control and diabetic animals were selected to receive daily doses of esculin (50 mg/kg), during 8 weeks. The animals were placed in metabolic cages at the eighth week of protocol for 24 h urine collection and a small aliquot of blood was collected for biochemical analysis. After this procedure, the animals were euthanized and the remaining kidney was stored for histopathological analysis, Western blotting and mitochondrial high-resolution respirometry.

KEY FINDINGS

Although esculin did not change metabolic parameters, renal biochemical function, neither TBARS in DM rats, esculin reduced P2X7 levels in these animals and restored mitochondrial function via glycolysis substrates and β-oxidation. Besides, at the histological analysis, we observed that esculin reduced inflammatory infiltrates and collagen IV deposits as compared to diabetic group.

SIGNIFICANCE

Esculin attenuated the development of renal injuries caused by hyperglycemia, proinflammatory and oxidative mechanisms mediated by P2X7 receptor, as seen by histological findings and improved mitochondrial function in diabetic animals. This suggests that esculin could be used as an adjuvant therapy to prevent the diabetic nephropathy.

Precocious obesity predisposes the development of more severe cisplatin-induced acute kidney injury in young adult mice

Obesity and its consequences can damage the kidney over time. However, less is known about the impact of developing overweight/obesity during childhood on the kidney in adulthood and the renal impact of a superimposed acute kidney injury (AKI). This study evaluated the effect of obesity induced by a high-fat diet initiated soon after weaning on the adult life of mice and their response to superimposed nephrotoxic effects of cisplatin. C57BL/6 post-weaning mice (3 weeks old) were divided into a control group (CT, n = 12) and a high-fat diet group (HF, n = 12). After 9 weeks, animals were further divided into the following groups: CT, CT treated with a single dose of cisplatin (CTCis, 20 mg/kg, i.p.), HF and HF treated with cisplatin (HFCis). The HF group exhibited higher body weight gain compatible with a moderate obesity. Obese mice presented increased visceral adiposity, hyperkalemia, sodium retention, glomerular hyperfiltration and proteinuria, without any significant changes in blood pressure and glycemia. AKI induced by cisplatin was exacerbated in obese animals with a 92% reduction in the GFR versus a 31% decrease in the CTCis group; this sharp decline resulted in severely elevated serum creatinine and urea levels. Acute tubular necrosis induced by cisplatin was worsened in obese mice. The HFCis group exhibited robust systemic and intrarenal inflammation that was significantly higher than that in the CTCis group; the HFCis group also showed a higher degree of renal oxidative stress. In conclusion, the moderate degree of obesity induced shortly after weaning resulted in mild early renal alterations, however, obese young animals were prone to develop a much more severe AKI induced by cisplatin.

Glucose-insulin infusion reduces kidney injury in an experimental model of ischemic nephropathy

BACKGROUND/AIMS

intensive insulin therapy may reduce renal dysfunction during severe illness in adult patients. We evaluated the effects of insulin-glucose (IG) in normoglycemic rats subjected to ischemia-reperfusion (I/R)-induced acute kidney injury.

METHODS

animals received intravenous infusions of 5% glucose [control (C)] or IG for 96 h. I/R was induced by means of bilateral renal artery clamping for 45 min. Serum creatinine (sCr) and urea (sUr) levels were evaluated before and up to 72 h after injury. Tissue samples were evaluated 72 h after I/R on a scale of 0 (normal) to 4 (above 75%) in relation to the extent of kidney injury.

RESULTS

after 48 h of I/R, sCr and sUr were increased 2- to 4-fold in C as compared to sham-operated controls (p < 0.05). IG produced significant improvements in renal function (p < 0.05). Upon histopathological analysis, the IG group presented less tubular damage in comparison to the C group: level 1, 60 versus 20%; level 2, 20 versus 30%; level 3, 20 versus 30%, and level 4, 0 versus 20%, respectively (n = 10; p = 0.057).

CONCLUSION

our results suggest that IG infusion attenuates the renal damage induced by severe I/R independently of blood glucose control. This strategy may constitute a therapeutic option for the prevention and treatment of ischemic renal injury.