Objective: To investigate the rule of the change in plasma concentration of free amino acids during early postburn stage in severely scalded rats, so as to provide assistance for the study of postburn abnormal metabolism of skeletal muscle.
Methods: Male Wistar rats inflicted by 30% TBSA III degree scalding were employed as the model and were randomly divided into normal (C), 2 postburn hour (PBH), 6PBH, 12PBH and 24PBH groups, with 8 rats in each group. Plasma concentrations of free amino acids was determined by automatic amino acid analyzer. At the same time, the plasma contents of alanine aminotransferase (ALT), aspartate aminotransferase (AST), cortisol, TNF and IL-6 were also assayed.
Results: There was adecreasing tendency in varying degrees in plasma concentration of all amino acids at each time points within 24 PBHs although there was no obvious difference in total amino acids content at each time point. The plasma level of BCAA decreased evidently at 2 PBH and increased obviously at 12 PBH, while the plasma levels of aromatic amino acids (AAA) increased evidently at 12 and 24 PBHs. In addition, the BCAA/AAA ratio showed no change. The ratio of phenylalanine to tyrosine increased significantly at all postburn time points except that of 2PBH. The plasma levels of ALT, AST increased obviously at all postburn time points (P < 0.01). Plasma cortisol levels in all scalding groups were markedly higher than that in C group (P < 0.01), and reached peak level at 12 PBH. Plasma contents of TNFalpha and IL-6 increased significantly (P < 0.01). Whereas the changes in IL-6 and cortisol were obviously and positively correlated to the changes in 3 -- mH and Phe/Tyr.
Conclusion: There were significant changes in plasma contents of free amino acids during early postburn stage in scalded rats, which might be related to the early excessive release of inflammatory mediators and enhanced degradation of skeletal muscle and impairment of hepatic function. The mechanism of the change needs to be further studied.