| On the base of 17-crystalline amino acids(17AA),we have designed five amino acids. First, we determine the best amino acids formulas by the results of enteral nutrition experiment in traumatized rats. Second, the new 20-crystalline amino acids (20AA) solution which enriched with branched-chain amino acids(BCAA) and glutamine(Gln) are compared with 17AA and 18AA to observe the nutritional supportive effects of parenteral nutrition on traumatized rats. The main methods and results are as follows.1.The study of the new amino acid formulas.Based on the changes of plasma and tissue amino acid profiles in burned patients,the composition of 17AA,advances in the field of nutritional pharmacology of amino acids.five amino acids formulas(A, B, C, D, E) were designed. The dominant characteristics for each formulas is :A contains 12% Gln,B contains a rich BCAA (30%), and C, D, E are common in the rich containing of Gln and BCAA, but are different in the proportion of other amino acids. Especially, E contains 16%Gln , aspartic acid and taurine.2. The estabolishment of trauma models in rats and the evaluation of the new amino acids formulas in total enteral nutrition.First, the animal model of trauma in rats was set up. The results showed that from 3 days after operation, the concentrations of prealbumin and albumin in plasma were significantly reduced than normal. BCAA, CEAA, and Asparagine levels in plasma were decreased intraumatized rats. The concentrations of MDA in plasma were increased, while the SOD activities were decreased. Thymus and spleen were shrinked, and the morphological changes of small intestines was also observed.Wistar rats were randomly assigned to each group. After injured, animals were fed with isonitrogenous diets ad libitum. According to formulas, the amino acids mixtures as the only nitrogen source were incorporated in semisynthetic diets. In each experiment, 17AA was used as control.The results showed that 12% Gin enhanced the growth of small bowel mucosa;30% BCAA accelerated the wound healing. However, there is different efficacy among formulas C, D and E. Formula C was found disadvantageous for trauma rats;Formula D remarkedly increased the contents of DNA and protein of small bowel mucosa, meanwhile it also promoted wound healing;Formula E had beneficial effects on injured rats. Compared with 17AA, 20AA improve better nitrogen balance, reduce oxyradical damage, increase spleen lymphocyte blastogenesis, the contents of hydroyproline and tensile strengths, improve the growth of intestinal mucosa, enhance the expression fo some growth factors such as EGF-, TGF0K bFG. These results suggest that E is an ideal formula for injury rats. However, further investigation is necessary to evaluate wheather it is advantageous in parenteral nutrition.3. The estabolishment of central vein infusion models in rats and the study of nutritional effect of a new amino acids formulas in total parenteral nutrition.First, we set up the animal model of central vein infusion in rats successfully. The rats were infused different amino acid solutions for at least 14 days without any restriction. The above experiments laythe foundation for the assessment of wound healing and nutritional support.Then, a new 20-crystalline amino acids(20AA) solution are compared with 17AA and 18AA to observe the nutritional supportive effects of parenteral nutrition on traumatized rats. The dose-effects of 20AA solution are observed too. The periods of infusion amino acids solution was 3 and 7 days separatedly.The results showed that all the three amino acids solutions have good nutritional effects on traumatized rats. However, 20AA was more beneficial than 17AA and 18AA in improving optimizing protein metabolism, enhancing antioxidative capacity and immune function and improving wound healing and the growth of intestinal mucosa.In a short word, the above results may provide some clues for the study of the new amino acids solution to promote wound healing and the new nutritional pharmacology effects of some non-essential amino acids.
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