Rat livers were cold stored (0°C-48 Hs) in University of Wisconsin (UW) solution. To reduce cold preservation/reperfusion injuries, three concentrations (50, 100 and 250 μM) of S-nitrosoglutathione (GSNO) were studied. GSNO, which releases Nitric Oxide (NO), was added into UW solution during the cold storage period. NO is a vasodilator that acts on hepatic microvascular system protecting the liver from preservation/reperfusion injuries. We compared five groups of livers: a) Normal control (livers neither stored not reperfused); b) cold stored livers for 48 Hs in UW; c) cold stored livers for 48 Hs in UW + 50 μM GSNO; d) cold stored livers for 48 Hs in UW + 100 μM GSNO; e) cold stored livers for 48 Hs in UW + 250 μM GSNO. Groups b, c and e were reperfused after cold storage. Pieces of rat livers were histological processed for paraffin embedded after reperfusion. Liver slices were stained with Direct Red 80 - Fast Green and analyzed with polarized microscopy to differentiate collagen type I from type III.
Except livers from group a that showed abundant collagen fibers (collagen type I: red, yellow, white or orange – thin white arrows; collagen type III: green – white empty arrows), all the other groups present less amount of collagen fibers. While collagen type III seem not to be affected by the treatment (cold storage/reperfusion), collagen type I was drastically diminished. Livers from group d conserved some fibers of collagen type I, while the ones of groups b, c and e practically lost them. It seemed that 100 μM was the preeminent concentration of GSNO to prevent the complete lost of collagen type I during cold storage in UW solution following by reperfusion.
