Protective effects of glutamine preconditioning on ischemia-reperfusion injury in rats.

BACKGROUND: Hepatic ischemia-reperfusion injury is a common phenomenon in hepatic surgical procedures and can result in further severe damage. This study aimed to investigate the protective effects of glutamine preconditioning on hepatic ischemia-reperfusion injury in rats and its dose-dependency.
METHODS: Thirty-two healthy male Wistar rats were randomly divided into four groups (n=8 per group). One group received 0.9% NaCl (control) and the other three received glutamine (Gln groups) 4 hours before ischemia. The Gln groups were named GL, GM, and GH according to the glutamine dose. The liver was subjected to 1 hour of ischemia and 2 hours of reperfusion. Two hours later, the levels of alanine aminotransferase (ALT), intracellular free calcium (Ca2+), and activity of Na+/K+ adenosine triphosphatase (ATPase) and superoxide dismutase (SOD) were assessed, and liver tissue sections were examined under a microscope.
RESULTS: The Gln and control groups differed in the concentration of intracellular free calcium (P<0.05), and the activity of Na+/K+ ATPase and SOD in the Gln groups was higher than in the control group (P<0.05). The ALT level was lower in the GM and GH groups than in the control group (P<0.05). The levels of Na+/K+ ATPase and SOD rose gradually with increasing glutamine dose (P<0.05), and the concentration of Ca2+ declined gradually with increasing glutamine dose (P<0.05). The degree of hepatocyte injury was milder in the Gln groups than in the control group.
CONCLUSIONS: Glutamine preconditioning protected effectively against hepatic ischemia-reperfusion injury. These protective effects were related to the dose of glutamine and due to the reduction of intracellular calcium overload and the improvements in the activity of Na+/K+ ATPase and SOD.