Inhibition of neutral sphingomyelinase decreases elevated levels of nitrative and oxidative stress markers in liver ischemia–reperfusion injury

Oxidative stress and excessive nitric oxide production via induction of inducible nitric oxide synthase (NOS)-2 have been shown in the pathogenesis of liver ischemia–reperfusion (IR) injury. Neutral sphingomyelinase (N-SMase)/ceramide pathway can regulate NOS2 expression therefore this study determined the role of selective N-SMase inhibition on nitrative and oxidative stress markers following liver IR injury. Selective N-SMase inhibitor was administered via intraperitoneal injections. Liver IR injury was created by clamping blood vessels supplying the median and left lateral hepatic lobes for 60 min, followed by 60 min reperfusion. Nitrative and oxidative stress markers were determined by evaluating NOS2 expression, protein nitration, nitrite/nitrate levels, 4-hydroxynonenal (HNE) formation, protein carbonyl levels and xanthine oxidase/xanthine dehydrogenase (XO/XDH) activity. Levels of sphingmyelin and ceramide in liver tissue were determined by an optimized multiple reaction monitoring method using ult...