Biochemical Alterations Of Amino Acids, Neurotransmitters And Hepatic Functions After Thermal Injury In Rats

Abstract

Thermal injury in human and animals models may be complicated by dysfunction to organs distant from the original burn wound. The physiopathological events following thermal injury are not limited to the surface effects of heat but are also related to an acute inflammatory reaction with increased muscle protein breakdown. The aim of the present study was to investigate the biochemical alterations of some amino acids, brain neurotransmitters and hepatic functions during postburn stage in scalded rats. Male Wistar rats inflicted by 30% total body surface area (TBSA) were employed as the model and were randomly divided into 5 groups; normal sham control, 1,3,5 & 7 days postburn groups, with 8 rats in each groups. Serum levels of IL-6 was estimated by ELISA method. Serum concentrations of amino acids were determined by amino acid analyzer. Levels of homocystein and glutathione were estimated by HPLC method. At the sametime, brain neurotransmitters, serum ALT, AST, ALP and γ-GT levels were also assayed. There was a decreasing tendency in varying degrees in serum concentrations of most amino acids at each time points. Serum homocysteine level in all scalding groups were markedly lower than that in sham control group at all postburn time points. GSH concentration was significantly decreased at D5 and D7, however, the concentration of GSSG was increased at D1, D3 and D7 and GSH/GSSG ratio was decreased at D1, D3, D5 and D7 postburn when compared to the sham control. There was increasing tendency in brain concentration of norepinephrine and dopamine, while the level of brain serotonin showed a pronounced decrease after one day following burn injury and 3 &5 days postburn its levels increased significantly when compared to sham group. At the seventh day following burn, serotonin level was found to be replenished back to that of the sham control group. The serum levels of ALT, AST, ALP and γ-GT were increased obviously at all postburn time points. In conclusion, we found that, There were significant changes in serum contents of amino acids and brain neurotransmitters during postburn stage in scalded rats, which might be related to the early excessive release of inflammatory mediators, enhanced degradation of skeletal muscle and impairment of hepatic function.

Keywords: burns, IL-6, neurotransmitters, liver, amino acids, glutathione, homocysteine

Egyptian Journal of Biochemistry and Molecular Biology Vol. 26 (2) 2008: pp. 13-28