AIM: To evaluate the effect of ANP on warm I/R injury in a porcine THVE model. METHODS: Miniature pigs (mini-pigs) weighing 16-24 kg were observed for 120 min after reperfusion following 120 min of THVE. The animals were divided into two groups. ANP (0.1 μg/kg per min) was administered to the ANP group (n = 7), and vehicle was administered to the control group (n = 7). Either vehicle or ANP was intravenously administered from 30 min before the THVE to the end of the experiment. Arterial blood was collected to measure AST, LDH, and TNF-α. Hepatic tissue blood ? ow (HTBF) was also measured. Liver specimens were harvested for p38 MAPK analysis and histological study. Those results were compared between the two groups. RESULTS: The AST and LDH levels were lower in the ANP group than in the control group; the AST levels were signifi cantly different between the two groups (60 min: 568.7 ± 113.3 vs 321.6 ± 60.1, P = 0.038 < 0.05, 120 min: 673.6 ± 148.2 vs 281.1 ± 44.8, P = 0.004 < 0.01). No signifi cant difference was observed in the TNF-α levels between the two groups. HTBF was higher in the ANP group, but the difference was not signif icant. A signifi cantly higher level of phosphorylated p38 MAPK was observed in the ANP group compared to the controlgroup (0 min: 2.92 ± 1.1 vs 6.38 ± 1.1, P = 0.011 < 0.05).Histological tissue damage was milder in the ANP group than in the control group. CONCLUSION: Our results show that ANP has a protective role in I/R injury with p38 MAPK activation in a porcine THVE model. METHODS: Miniature pigs (mini-pigs) weighing 16-24 kg were observed for 120 min after reperfusion following 120 min of THVE. The animals were ANP (0.1 μg / kg per min) was administered to the ANP group (n = 7), and vehicle was administered to the control group (n = 7). Either vehicle or ANP was intravenously administered from 30 min Before the THVE to the end of the experiment. Arterial blood was collected to measure AST, LDH, and TNF-α. RESULTS: The AST and LDH levels were lower in the ANP group than in the control group; the AST levels were signifiantly different between the two groups (60 min: 568.7 ± 113.3 vs 321.6 ± 60.1, P = 0.038 <0.05, 120 min: 673.6 ± 148.2 vs 281.1 ± 44.8, P = 0.004 <0.01 ) No signifi cant difference was observed in the TNF-α levels between the two groups. HTBF was higher in the ANP group, but the difference was not signif icant. A signifi cantly higher level of phosphorylated p38 MAPK was observed in the ANP group compared to the control group (0 min: 2.92 ± 1.1 vs 6.38 ± 1.1, P = 0.011 <0.05). CONCLUSION: Our results show that ANP has a protective role in I / R injury with p38 MAPK activation in a porcine THVE model.