Compensatory renal growth and mitochondrial function: the influence of warm ischemia and reperfusion

Adipose tissue derived mesenchymal stem cell transplantation in the treatment of ischemia/reperfusion induced acute kidney injury in rats. Application route and therapeutic window1

PURPOSE

To evaluate renal repair in rats who had renal infarction induced by the obstruction of blood flow in the renal artery and were treated with transplantation of adipose tissue derived mesenchymal stem cell.

METHODS

16-week-old Wistar rats (n=72) were used, submitted to celiotomy and had of the renal artery and vein clipped for 24 hours. The animals were randomly assigned to 10 experimental homogeneous groups, corresponding to the treatments with phosphate-buffered saline (PBS) or adipose tissue derived mesenchymal stem cell (ADSC), duration of application (24 or 48 hours), and site of transplantation (lateral vein of the tail or intrarenal). After the treatments were performed, at 8 and 31 days, four animals in each group were subjected to left nephrectomy for histological studies.

RESULTS

Histologically, a higher amount of cell debris and tubules devoid of the epithelium and a higher degree of necrosis were observed in the groups treated with PBS, as opposed to a low degree of necrosis and higher tubular vascularization in the groups treated with ADSC, particularly in the group treated with intrarenal ADSC 48 hours after injury.

CONCLUSION

The transplantation of ADSC positively contributed to the replacement of necrotic tissue by renal tubular cells, vascularization of the renal parenchyma, and restoration of the organ function.

Nephroprotective effects of (-)-α-bisabolol against ischemic-reperfusion acute kidney injury

BACKGROUND

Ischemia/reperfusion (I/R) in kidney is commonly related to acute kidney injury (AKI), essentially through oxidative stress. (-)-α-Bisabolol is a sesquiterpene isolated from the essential oil of a variety of plants, including chamomile, which has important antioxidant activity.

STUDY DESIGN

This study intends to evaluate the nephroprotective activity of (-)-α-bisabolol (Bis) in both in vivo and in vitro models of kidney I/R.

METHODS

Male Wistar rats were submitted to right nephrectomy, followed by ischemia by clamping of the renal artery in the left kidney for 60min. and 48h of reperfusion. The animals were treated orally with Bis (100mg/kg) or vehicle for 24h after reperfusion, and placed in metabolic cages, to evaluate water consumption, diuresis, urinary osmolality, classic biochemical markers and urinary KIM-1 (kidney injury molecule-1). Additionally, the left kidney was collected for histological evaluation and determination of glutathione (GSH) and Thiobarbituric Acid Reactive Substances (TBARS) levels. Tubular epithelial cells LLC-MK2 were used to assess Bis effect on in vitro I/R, by MTT assay. It was performed the cellular respiration tests by flow cytometry: evaluation of the production of cytoplasmic reactive oxygen species by DCFH-DA assay and mitochondrial transmembrane potential analysis with the dye rhodamine 123.

RESULTS

I/R caused alterations in diuresis, water intake, urinary osmolality, plasmatic creatinine, urea and uric acid, creatinine clearance, proteinuria and microalbuminuria. Treatment with Bis ameliorated all of these parameters. Also, KIM-1 level enhanced by I/R was also diminished in groups treated with Bis. The histological examination showed that Bis attenuated the morphological changes caused by I/R, markedly vascular congestion and intratubular deposits of proteinaceous material. Additionally, Bis was able to reduce the changes observed in TBARS and GSH levels in kidney tissue. In in vitro assay, Bis was capable to partially protect the cell lineage against cell damage induced by I/R.

CONCLUSION

(-)-α-Bisabolol has a nephroprotective effect in kidney I/R, with antioxidant effect. Moreover, this result seems to be associated to a direct protective effect on tubular epithelia.

Lovastatin protects mithochondrial and renal function in kidney ischemia-reperfusion in rats

PURPOSE

To investigate the effect of lovastatin on renal ischemia followed by reperfusion.

METHODS

Thirty one Wistar rats submitted to left renal ischemia for 60 minutes followed by contralateral nephrectomy were divided into two groups: A (n =17, control, no treatment), and B (n=14, lovastatin 15 mg/kg/day p.o. ten days before ischemia). The animals were sacrificed at the end of ischemia, after 24 hours and at seven days after reperfusion. Survival, serum urea and creatinine levels and renal mitochondrial function were evaluated.

RESULTS

Mortality was 29.4% in group A and 0.7% in group B. Urea and creatinine levels were increased in both groups, but the values were significantly lower in group B. Mitochondrial function showed decoupling in 83.4% of group A, as opposed to 38.4/% of group B.

CONCLUSIONS

The result shows a protective action of renal function by lovastatin administered before ischemia/reperfusion. Since most of the mitochondrial fraction presented membranes with the ability to maintain ATP production in group B, stabilization of the mitochondrial membrane should be considered as part of the protective action of lovastatin on renal function in ischemia/reperfusion.

Effect of glutamine on the total antioxidant system of rats subjected to renal ischemia and reperfusion

PURPOSE: To evaluate the protective effects of glutamine administered before renal ischemia-reperfusion on plasma antioxidant protection, and lung and renal tissue injury. METHODS: 33 rats underwent right nephrectomy. On the eighth postoperative day, animals were randomized into three groups (n=11): glutamine, control and sham. Each group of animals received, by gavage, a particular diet for 7 days. On day 14 following nephrectomy, the animals were subjected to left renal ischemia-reperfusion. After this, blood samples were collected and the animals were killed. At necropsy the kidney and lung were removed for histology. RESULTS: The levels of total antioxidant capacity were higher in the glutamine group and control group compared with the sham group. The levels of glutathione peroxidase in both the sham and glutamine groups were higher when compared with the control group (p<0.05). The level of superoxide dismutase in the sham group was clearly higher than that in the glutamine and control groups. Histological examination showed no differences between the three groups. CONCLUSION: Prior intake of glutamine improves total antioxidant capacity and increases glutathione peroxidase levels in rats subjected to renal ischemia-reperfusion.