Effects of glutamine on changes of nuclear factor-kappa B in acute lipopolysaccharide lung injury: experiment with rats

Abstract

To investigate the effects of glutamine on the changes of nuclear factor (NF)-kappaB and lung pathology in acute lung injury. Forty SD rats underwent injection of lipopolysaccharide (LPS) 5 mg/kg into the femoral vein, and were randomly divided into 4 equal groups: Group B: undergoing injection of glutamine 0.75 g/kg into the femoral vein 1 h before LPS injection, Group C undergoing injection of glutamine and LPS simultaneously, and Group D undergoing injection of glutamine 1 h after LPS injection, and Group E without glutamine injection. Another 10 rats underwent injection of normal saline to be used as controls (Group A). Four hours after the LPS injection the rats were killed with their lungs taken out RT-PCR was used to detect the level of nuclear factor (NF)-kappaB mRNA expression. ELISA was used to detect the tumor necrosis factor (TNF) - in lung. The activity of superoxide dismutase (SOD) was examined by hydroxylamine method, and the malondialdehyde level was determined by thiobarbituric acid (TBA) method. The lung NF-kappaB mRNA expression levels and TNF- levels of Groups B, C, D, and E were all significantly higher than that of Group A (all P < 0.01). The lung NF-kappaB mRNA expression levels and TNF- levels of Groups C and D were all significantly lower than those of Group B (P < 0.01). However, there were no significant differences in lung NF-kappaB mRNA expression level and TNF- level between Group B and Group E (both P > 0.05). The SOD activity of Group B was significantly lower than that of Group A and the MDA content of Group B was significantly higher than that of Group A (both P < 0.05). The SOD activity levels of Groups C and D were significantly higher than that of Group B and the MDA content of Groups C and D were significantly lower than that of Group B (P < 0.01 or P < 0.05). However there were no significant differences in lung SDD activity and MDA content between Groups B and E (both P > 0.05). Obvious inflammatory changes were seen in the lungs of Groups B and E at the similar extent. Only slight infiltration could be seen in Groups C and D. The lung of Group A was normal. Early glutamine administration protects the lung against acute LPS injury. The mechanism may be inhibition of the overexpression of NF-kappaB mRNA.