Protective effect of melatonin on acute necrotizing pancreatitis associated with renal injury in rats

Objective To study the effects of melatonin on acute necrotizing pancreatitis(ANP) associated with renal injury. Methods Seventy-two rats were randomly divided into control group(n=24),ANP group(n=24),and melatonin treatment group (n=24).ANP group was given intraperitoneal injection of 6%L-arginine(L-Arg) 1.5g/kg 3 times to establish ANP model. Treatment group was given intraperitoneal injection of 1%melatonin 50μg/kg one time 30 minutes before the first injection of L-arginine. Control group was done in the same way with equivalent dose of normal saline injection.The rats were killed separately on 6h,12 h,and 24 h after the last intraperitoneal injection.The level of hemodiastase(AMY) and serum creatinine(Cr),the contents of malon- dialdehyde(MDA) and myeloperoxidase(MPO) in kidney tissue were detected.The histological changes in kidneys were observed under the light microscope and the renal pathology score was calculated.Results The values of AMY,Cr,MDA,and MPO in ANP group on the corresponding time points were significantly higher than those in control group,respectively(P0.01).Meanwhile kidney tissue injury was more serious and pathology score was higher.The values of AMY,Cr,MDA,and MPO in treatment group were lower than those in ANP group on the corresponding time points(all P0.01),Pathological changes in kidney and score were significantly decreased (all P0.01).Conclusions Melatonin protects the kidneys with antioxidant and anti-inflammatory effects.