ABSTRACT
Objective To evaluate the effect of methylene blue pertreatment on acute kidney injury induced by sepsis in rats.Methods Ninety male Sprague-Dawley rats,aged 1.5-2.5 months,weighing 200-250 g,were randomly assigned into 3 groups (n =30 each) using a random number table:sham operation group (S group),cecal ligation and puncture (CLP) group and methylene blue group (MB group).The rats were anesthetized with 10％ chloral hydrate 350 mg/kg.Normal saline 0.8 ml was injected via the caudal vein in and CLP groups,while 10％ methylene blue 15 mg/kg (in normal saline 0.8 ml) was injected via the caudal vein in group MB.Sepsis was induced by CLP after the end of administration in CLP and MB groups.Twenty animals in each group were chosen and observed for 72 h survival rate.Ten animals were sacrificed in each group at 18 h after operation and kidney specimens were removed for microscopic examination and for determination of the expression of poly (ADP-ribose) polymerase (PARP-1) using immunohistochemistry and Western blot.Blood samples were taken from the heart for determination of serum concentrations of blood urea nitrogen (BUN),creatinine (Cr),cystatin C and neutrophil gelatinase-associated lipocalin (NGAL).Results Compared with group S,the survival rate was significantly decreased at 24,48 and 72 h after operation,and the serum concentrations of BUN,Cr,cystatin C and NGAL and expression of PARP-1 in kidney tissues were increased in CLP and MB groups (P ＜ 0.05).Compared with group CLP,the survival rate was significantly increased at 24 and 48 h after operation,and the serum concentrations of BUN,Cr,cystatin C and NGAL and expression of PARP-1 in kidney tissues were decreased in group MB (P ＜ 0.05).The pathological changes were significantly attenuated in group MB as compared with group CLP.Conclusion Methylene blue pertreatment can attenuate acute kidney injury induced by sepsis in rats through down-regulating the expression of PARP-1.