Evaluation of the mortality rate caused by different periods of selective portal vein occlusion in rats

The Protective Effect of Zinc Against Liver Ischaemia Reperfusion Injury in a Rat Model of Global Ischaemia

BACKGROUND

Ischaemia-reperfusion injury (IRI) is a major obstacle during liver transplantation and resection surgeries for cancer, with a need for effective and safe drugs to reduce IRI. Zinc preconditioning has been shown to protect against liver IRI in a partial (70%) ischaemia model. However, its efficacy against a clinically relevant Pringle manoeuvre that results in global liver ischaemia (100%) is unknown.

AIMS

The aim of this study was to test the efficacy of zinc preconditioning in a rat model of global liver ischaemia.

METHODS

Rats were preconditioned via subcutaneous injection of 10 mg/kg of ZnCl₂, 24 h and 4 h before ischaemia. Total liver ischaemia (100%) was induced by placing a clamp across the portal triad for 30 min. Liver injury was assessed by serum alanine transaminase (ALT) and aspartate transaminase (AST) levels in blood taken before ischaemia (baseline) and at 1, 2, 4, 24, 48, 72, 96 and 120 hours after ischaemia. Animals were culled after 7 days, and the harvested livers were histologically analysed.

RESULTS

On a two-way repeated-measures analysis of variance, there was a statistically significant (p = 0.025) difference in the mean ALT levels between saline- and ZnCl₂-treated groups. Specifically at 24 h after ischaemia, the ALT (341 ± 99 U/L) and AST (606 ± 78 U/L) in the zinc-treated group were significantly less than the ALT (2863 ± 828 U/L) and AST (3591 ± 948 U/L) values in the saline-treated group. Zinc significantly reduced neutrophil infiltration and necrosis compared with the saline control.

CONCLUSION

Zinc preconditioning reduces the overall hepatocellular damage from IRI. These results lay the foundation to assess the benefit of zinc preconditioning for clinical applications.

Abdominal compartment syndrome caused by a bulimic attack in a bulimia nervosa patient

We present a rare case of abdominal compartment syndrome due to a bulimic attack in a 19-year-old female patient with bulimia nervosa. She was admitted to our emergency room with complaints of progressive abdominal pain following bulimia. Computed tomography showed dilated stomach with food and air pressed other visceral organs and major abdominal vessels. Decompression using nasogastric tube or gastric lavage tube failed. At laparotomy, we performed gastrotomy and decompression was performed. After decompression, she fell into hypovolemic shock due to bleeding in the intra-gastric and peritoneal cavity. Twelve hours after the operation, the patient died due to refractory hypovolemic shock from uncontrolled bleeding following decompression of abdominal compartment. It should keep in mind that binge-eating habits in patients with bulimic nervosa could cause abdominal compartment syndrome due to gastric distension and this may be a potentially fatal condition.

Induction of intestinal ischemia reperfusion injury by portal vein outflow occlusion in rats

BACKGROUND

Intestinal ischemia can occur from mesenteric artery (MA) occlusion and portal vein (PV) occlusion. The degree and mechanisms of ischemia/reperfusion (I/R) injury in these conditions may differ. Metabolic changes are seen early in I/R. This study compares tissue histology, inflammation, and metabolic response during small bowel I/R due to superior MA or PV occlusion.

METHODS

Anesthetized male Wistar rats (250-300 g) underwent laparotomy followed by MA or PV occlusion for 40 min. After 120 min of reperfusion, small bowel tissue was collected. The expression of heat shock protein (HSP)-32 and HSP70 was evaluated to compare physiological stress responses between groups. Metabolic profiles were obtained using (1)H-nuclear magnetic resonance spectroscopy (NMR)-based quantitative metabolomics. Histological injury of small bowel was graded from 0 (normal) to 4 (extensive ischemic damage).

RESULTS

Protein expression of HSP32 and HSP70 increased when compared to sham but was not different in the MA I/R and PV I/R groups. Metabolic profiles demonstrated decreased glucose levels and highly elevated tissue lactate and amino acids and fatty acids following I/R, with more pronounced changes with PV occlusion. Lipid peroxidation was equally increased in both groups, while depletion of reduced glutathione (GSH) was more severe with MA occlusion. The epithelial necrosis score was higher with MA (3.5 ± 0.6) than with PV occlusion (2.3 ± 0.8).

CONCLUSIONS

Histological injury of the intestine is less pronounced following PV occlusion, most likely due to higher oxygen and substrate availability during I/R by PV occlusion. This conclusion is supported by a more pronounced metabolic synthetic response (increased glycolysis and fatty acid and amino acid accumulation) with PV occlusion, while oxidative stress was higher with MA occlusion. The inflammatory response showed little difference between the groups.