Mechanism of ischemia-reperfusion injury-induced gastric oxidative damage during perioperative period of liver transplantation

Abstract

Objective To investigate the occurrence rule and mechanism of ischemia-reperfusion injury (IRI)-induced gastric oxidative damage during perioperative period of liver transplantation. Methods Twenty-eight SD rats were randomized into 4 groups according to the random number table. The model of orthotopic autologous liver transplantation was established in 3 groups, which were 4 h, 8 h, 16 h group according to the reperfusion time of the liver grafts. The other group was set as Sham group. Gastric tissues were stained with HE to observe pathological changes of gastric mucosal injury. Superoxide anion (O2-), malondialdehyde (MDA), glutathione (GSH) and glutathione peroxidase (GSH-PX) in gastric tissues were detected. The expression of thioredoxin (Trx)-2 in gastric tissues was detected by Western blot. The comparison on experimental data was conducted using one-way analysis of variance and LSD-t test. Results In 4 h group, congestion, edema and hemorrhage were observed in deep stratum and submucous stratum of stomach, as well as disorganized glands, regional hemorrhage and necrosis, and erosion was observed deep to the muscularis mucosa. In 8 h group and 16 h group, gastric mucosal injury was alleviated, and only congestion and edema in superficial and deep layer were observed. In Sham group, the epithelium structure of most gastric mucosa was intact. The O2- and MDA of 4 h group were respectively (185±26) U/mg and (0.4±0.1) nmol/mg and those of 8 h group were respectively (192±59) U/mg and (0.5±0.1) nmol/mg, which were significantly higher than (102±34) U/mg and (0.2±0.1) nmol/mg of Sham group (LSD-t=4.99, 4.23 and 6.37, 4.52; P<0.05). GSH and GSH-PX of 4 h group were respectively (17±6) mg/g and (781±174) U/mg and those of 8 h group were respectively (15±4) mg/g and (750±160) U/mg, which were significantly lower than (30±6) mg/g and (1 162±215) U/mg of Sham group (LSD-t=-3.26, -4.01 and -3.78, -4.36; P<0.05). The O2-, MDA, GSH and GSH-PX of 16 h group were respectively (169±27) U/mg, (0.3±0.1) nmol/mg, (25±8) mg/g and (1 108±183) U/mg, and significant difference was observed comparing with 8 h group (LSD-t=-2.85, -3.46, 2.66, 3.69; P<0.05). The relative expression of Trx-2 in 4 h group and 8 h group were respectively 52±10 and 43±8, which were significantly lower than 125±16 of Sham group (LSD-t=-5.34, -6.23; P<0.05). The expression of Trx-2 in 16 h group was 160±18, which was significantly higher than that of 8 h group (LSD-t=4.75, P<0.05). Conclusion IRI causes gastric oxidative damage in the early phase after liver transplantation in rats, which may be associated with the decrease of Trx-2 expression, increase of active oxygen and decrease in organic antioxidative ability. Key words: Liver transplantation; Stomach disease; Antioxidant; Thioredoxin; Reactive oxygen species; Rat