Erythropoietin protects against cisplatin-induced nephrotoxicity by attenuating endoplasmic reticulum stress-induced apoptosis.
BACKGROUND
The anticancer drug cisplatin (CP)-induced nephrotoxicity associated with apoptosis plays crucial roles in tumor patients. Erythropoietin (EPO) has recently been shown to enhance recovery from CP-induced acute kidney injury (AKI) in rats by exerting anti-apoptotic effects. However, the molecular mechanisms of Erythropoietin protects against CP-induced AKI are not very clear. The present study investigated the protective effects of erythropoietin (EPO) against CP-induced nephrotoxicity and the possible mechanism in rats.


METHODS
Sprague-Dawley (SD) rats were randomly divided into four groups: (1) Control group (n=16): which received a single intraperitoneal injection of vehicle (0.9% saline; 5 mL/kg); (2) CP group (n=16): which received a single intraperitoneal injection of 10.0 mg/kg CP (previously dissolved at 2.0 mg/mL in 0.9% saline solution); (3) CP+rHuEPO group (n=16): which received rHuEPO (5000 U/kg) with co-injection of the LY294002 vehicle dimethyl sulfoxide (DMSO, 33.3 µL/kg; Sigma, St. Louis, MO, USA) by tail vein injection 2 days before CP administration, 15 min before CP administration, and 2 days after CP administration; (4) CP+rHuEPO+LY group (n=16): which received LY294002 (0.3 mg/kg) 10 min before rHuEPO administration by three injections into the tail vein at 2-day intervals beginning 2 days before CP administration. Apoptosis was assessed by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method. The expressions of C/EBP-homologous protein (CHOP), glucose-regulated protein 78 (GRP78), caspase-12, the phosphorylation of Akt, cleaved-caspase-3 and EPO receptor (EPOR) were measured after CP-treated. In addition, light microscopy and immunohistochemistry examinations were performed.


RESULTS
The levels of serum urea and creatinine were increased at 96 h after CP-administered group. The eHuEPO-administered group had significantly lower serum creatinine levels. CP caused an increase in TUNEL-positive cells that was accompanied and apoptotic cell death induced by CP was significantly abrogated by rHuEPO at 96h by morphological evidence of apoptosis. The over-expression of CP-induced endoplasmic reticulum (ER) stress markers (CHOP and GRP78) and activation of caspase-12 were suppressed by rHuEPO, which also attenuated the CP-induced suppression of phosphatidylinositol-3kinase/Akt (PI3K/Akt) signaling in rat kidneys. In addition, LY294002 diminished the effect of rHuEPO on renal protection and antiapoptosis.


CONCLUSIONS
Injection of rHuEPO enhance recovery from CP-induced AKI in rats by ameliorating renal functional impairment and exerting important anti-apoptotic effects. However, rHuEPO inhibited CP-induced AKI by a possible mechanism involving PI3K/Akt activation and the inhibition of ER stress-mediated apoptosis.
Department of Nephrology, 1st Affiliated Hospital of Harbin Medical University, PR China.
Deyang
D
Kong
Li
L
Zhuo
Changlu
C
Gao
Suozhu
S
Shi
Nan
N
Wang
Zhiyong
Z
Huang
Wenge
W
Li
Lirong
L
Hao
D058186:Acute Kidney Injury / Q000139:chemically induced / Q000378:metabolism* / Q000517:prevention & control; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053454:Caspase 12 / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology; D002945:Cisplatin; D003404:Creatinine / Q000097:blood; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004921:Erythropoietin / Q000494:pharmacology* / Q000627:therapeutic use; D006360:Heat-Shock Proteins / Q000378:metabolism; D008297:Male; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D051742:Transcription Factor CHOP / Q000378:metabolism; D014508:Urea / Q000097:blood; D000091342:Endoplasmic Reticulum Chaperone BiP
D053454:Caspase 12; D002867:Chromones; D002945:Cisplatin; D003404:Creatinine; D004791:Enzyme Inhibitors; D004921:Erythropoietin; D006360:Heat-Shock Proteins; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D051742:Transcription Factor CHOP; D014508:Urea; C497251:Ddit3 protein, rat; C051684:GRP78 protein, rat; D000091342:Endoplasmic Reticulum Chaperone BiP; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one