Prevention of ischemia/reperfusion injury by hepatic targeting of nitric oxide in mice

Macromolecular nitric oxide (NO) donors possessing the ability to target a specific type of liver cells were developed for delivering NO to the liver. Six NO molecules were covalently bound to mannosylated (Man) or galactosylated (Gal) bovine serum albumin (BSA) through an S-nitrosothiol linkage to obtain Man-poly SNO-BSA and Gal-poly SNO-BSA, respectively. The carrier parts of Man-poly SNO-BSA and Gal-poly SNO-BSA predominantly accumulated in the liver after intravenous injection in mice. In an ischemia/reperfusion injury mouse model, in which hepatic injury was induced by occluding the portal vein for 15 min followed by a 6 h reperfusion, the elevation of plasma alanine aminotransferase and aspartate aminotransferase levels was significantly inhibited by a bolus intravenous injection of Man-poly SNO-BSA or Gal-poly SNO-BSA, just before the start of reperfusion. In marked contrast, S-nitroso-N-acetyl penicillamine and NO-conjugated BSA, two classical S-nitrosothiols, had no statistically significant effects on the serum levels of the markers. The released NO in mouse liver was detected by electron spin resonance spectrometry only in the liver of mice receiving Man-poly SNO-BSA or Gal-poly-SNO-BSA. These findings indicate that Man-poly SNO-BSA and Gal-poly SNO-BSA are promising compounds for preventing hepatic ischemia/reperfusion injury by delivering pharmacologically active NO to the liver.