Effect of hydrogen-rich saline on acute kidney injury after orthotopic liver transplantation and the role of autophagy

Objective To investigate the effects of hydrogen-rich saline on acute kidney injury after orthotopic liver transplantation(OLT)in rats and the role of autophagy. Methods Fifty-six healthy adult male Sprague-Dawley rats, weighing 220–250 g, served as donors and recipients.Thirty-two recipient rats were randomly assigned into 4 groups using a random number table: sham operation group(group S), OLT group, hydrogen-rich saline group(group HS), and autophagy inhibitor chloroquine group(group CQ). In group S, laparotomy was performed, and the related blood vessels were isolated.The model of OLT was established in OLT, HS and CQ groups.In OLT and HS groups, normal saline and hydrogen-rich saline 6 ml/kg were injected, respectively, through the inferior vena cava at 5 min before anhepatic phase.In group CQ, chloroquine 60 mg/kg was injected intraperitoneally at 1 h before establishment of the model, and the other treatments were similar to those previously described in group HS.Blood samples were obtained at 6 h of neohepatic phase for determination of serum blood urea nitrogen(BUN)and creatinine(Cr)concentrations.After the end of blood sampling, the left kidneys were removed for determination of malondialdehyde(MDA)content(using thiobarbituric acid method), superoxide dismutase(SOD)activity(xanthine oxidase method), and cell apoptosis(using TUNEL), and for examination of the pathological changes of renal tissues.The damage to the renal tubules was scored.Apoptosis index(AI)was calculated.The expression of phosphorylated p53(p-p53), activated caspase-3, cytochrome c(Cyt c), microtubule-associated protein light chain 3Ⅱ(LC3Ⅱ), and Beclin-1 was detected by Western blot analysis. Results Compared with group S, the levels of BUN, Cr, and MDA, AI, and renal tubular damage score were significantly increased, the SOD activity was decreased, and the expression of activated caspase-3, Cyt c and LC3Ⅱ was up-regulated(P 0.05). Compared with group OLT, the levels of BUN, Cr, and MDA, AI, and renal tubular damage score were significantly decreased, the SOD activity was increased, the expression of activated caspase-3, Cyt c was down-regulated, and the expression of LC3Ⅱ, Beclin-1 and p-p53 was up-regulated in group HS(P 0.05). Conclusion Hydrogen-rich saline can attenuate acute kidney injury after OLT, and the mechanism is associated with activation of p53, enhancement of autophagy and inhibition of cell apoptosis in rats. Key words: Hydrogen; Liver transplantation; Kidney injury; Autophagy; Apoptosis