Additional effects of erythropoietin pretreatment, ischemic preconditioning, and N-acetylcysteine posttreatment in rat kidney reperfusion injury

Co-treatment with Esculin and erythropoietin protects against renal ischemia-reperfusion injury via P2X7 receptor inhibition and PI3K/Akt activation

Renal ischemia/reperfusion (RI/R) is a critical clinical outcome with slightly reported improvement in mortality and morbidity. Effective therapies are still crucially required. Accordingly, the therapeutic effects of esculin (ESC, LCESI-MS/MS-isolated compound from Vachellia farnesiana flowers extract, with reported P2X7 receptor inhibitor activity) alone and in combination with erythropoietin (EPO) were investigated against RI/R injury and the possible underlying mechanisms were delineated. ESC and EPO were administered for 7 days and 30 min prior to RI, respectively. Twenty-four hour following reperfusion, blood and kidney samples were collected. Results revealed that pretreatment with either ESC or EPO reduced serum nephrotoxicity indices, renal oxidative stress, inflammatory, and apoptosis markers. They also ameliorated the renal histopathological injury on both endothelial and tubular epithelial levels. Notably, ESC markedly inhibited P2X7 receptors and NLRP3 inflammasome signaling (downregulated NLRP3 and Caspase-1 gene expressions), whereas EPO significantly upregulated PI3K and Akt gene expressions, also p-PI3K and p-Akt levels in renal tissues. ESC, for the first time, demonstrated effective protection against RI/R-injury and its combination with EPO exerted maximal renoprotection when compared to each monotherapy, thereby representing an effective therapeutic approach via inhibiting oxidative stress, inflammation, renal tubular and endothelial injury, apoptosis, and P2X7 receptors expression, and activating PI3K/Akt pathway.

Carbamylated Erythropoietin Alleviates Kidney Damage in Diabetic Rats by Suppressing Oxidative Stress

The oxidative stress response plays an important role in the occurrence and development of diabetic kidney disease (DKD). It has become a new treatment target for DKD. In the current study, the effects of carbamylated erythropoietin (CEPO) on renal oxidative stress and damage in diabetic rats were examined. Thirty Sprague Dawley rats were intraperitoneally administered with 60 mg/kg streptozotocin to establish the diabetes model. The diabetic rats were randomly allocated into 4 groups (n=6 each): diabetes model group (DM group), DM + CEPO treatment group (DC group), DM + CEPO + EPO receptor (EPOR) blocking peptide treatment group (DCEB group), and DM + CEPO + CD131 blocking peptide treatment group (DCCB group). Meanwhile, a normal control group (NC group, n=6) was set up. Kidney tissues and blood samples were obtained for evaluation of oxidative stress and renal function. The results showed that diabetic rats exhibited increased oxidative stress in the kidney and early pathological changes associated with DKD. Treatment with CEPO reduced oxidative stress and attenuated renal dysfunction. However, diabetic rats treated with the combination of CEPO and EPOR blocking peptide or CD131 blocking peptide showed increased oxidative stress and reduced renal function when compared with CEPO treatment alone group. These results suggested that CEPO can protect against kidney damage in DKD by inhibiting oxidative stress injury via EPOR-CD131 heterodimers.

Protective Effect of N-Acetylcysteine Pretreatment on Acute Kidney Injury in Septic Rats

BACKGROUND

The aim of this study is to investigate the protective effect of N-acetylcysteine (NAC) pretreatment on acute kidney injury in septic rats.

METHODS

We constructed a septic rat model by cecal ligation and perforation (CLP) and assessed kidney tissue pathologic damage, renal function changes, and inflammatory factor levels. Meanwhile, we also assessed oxide and antioxidant enzyme levels in kidney tissues, observed apoptosis of kidney tissues, and evaluated mitochondrial membrane activity in renal cortical cells.

RESULTS

Pretreatment of NAC significantly alleviated pathologic damage of kidney tissues in septic rats; decreased the levels of serum creatinine, blood urea nitrogen, plasma neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1; and reduced the expression of tumor necrosis factor a, interleukin [IL]-1β, IL-6, and IL-8. Furthermore, NAC pretreatment reduced the level of protein-nitrotyrosine adducts and malondialdehyde in CLP-induced kidney tissues, while elevated the levels of superoxide dismutase, glutathione peroxidase, and catalase. Moreover, pretreatment of NAC reduced the number of apoptosis in kidney tissues induced by CLP, decreased the mRNA levels of caspase-3, caspase-9, cytochrome c, and poly ADP-ribose polymerase, and increased mitochondrial membrane activity in renal cortical cells (complex I/II/III/IV).

CONCLUSIONS

NAC pretreatment has protective effects on acute kidney injury induced by CLP, and its mechanism is closely related to anti-inflammatory, antioxidation, antiapoptosis, and regulation of mitochondrial function.