Evaluation of a glycine-rich amino acid solution for parenteral nutrition in endotoxemic rats.
OBJECTIVE
It has been shown recently that high amounts of glycine might have some pharmacologic effects (reduction of injury and mortality in endotoxemic rats), but its effects on the nutritional status and protein metabolism during injury are still unknown. The aim of this study was to compare the nutritional effects of a glycine-rich amino acid solution for parenteral nutrition (AFD) with a standard one (Vintene) (glycine, 15 vs. 9 g/L) in endotoxemic rats.


METHODS
Laboratory investigation.


METHODS
University laboratory.


METHODS
Male Wistar rats (198 +/- 11 g).


METHODS
Rats were operated to receive total parenteral nutrition (250 kcal/kg/day, 2 g N/kg/day) with amino acids supplied by either AFD (n = 9) or Vintene (V, n = 6). One day after surgery, corresponding to day 0 of the experiment and to the first day of full-strength total parenteral nutrition, the AFD and V group rats received an endotoxemic shock by intraperitoneal injection of lipopolysaccharide (Escherichia coli, 8 mg/kg). The rats were then studied over 3 days and compared with a healthy ad libitum-fed group (AL, n = 10).


RESULTS
The rats were weighed and urine was collected daily to determine nitrogen balance and 3-methylhistidine excretion. On day 3, the thymus, spleen, liver, intestinal mucosa, and muscles were weighed, and amino acids from plasma and tissues were analyzed. Lipopolysaccharide caused the classic endotoxemic shock, of similar intensity in the V and AFD groups (V and AFD not equal AL, p < .05): no weight gain, decreased nitrogen balance (day 3, AL 558 +/- 21, V 83 +/- 28, AFD 123 +/- 25 mg N/day), increased urinary 3-methylhistidine/creatinine excretion (day 3, AL 51 +/- 2, V 91 +/- 13, AFD 87 +/- 14 mumol/mmol), soleus (V -15% and AFD -26 % vs. AL) and thymus atrophy (V -36% and AFD -33%), and spleen hypertrophy (V 51% and AFD 83%). Compared with V solution, AFD has a reduced content of some essential amino acids and proline and an elevated content of glycine, aspartate, and glutamate. These differences were not reflected in tissue or plasma amino acids, except for plasma glycine, which in the AFD group was restored to the level of the AL group (AL 426 +/- 12 and AFD 379 +/- 50 vs. V 251 +/- 31 mumol/L, p < .05).


CONCLUSIONS
In endotoxemic rats, the nutritional effects of a glycine-rich AFD solution are similar to those of a standard amino acid solution for parenteral nutrition.
Loï
Cécile
C
Laboratoire de Biologie de la Nutrition, Faculté de Pharmacie, Paris 5, France.
Kana
Georgette
G
Blanc
Marie-Céline
MC
Genthon
Carine
C
Cynober
Luc
L
D000596:Amino Acids / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D003404:Creatinine / Q000652:urine; D004195:Disease Models, Animal; D019446:Endotoxemia / Q000139:chemically induced / Q000378:metabolism*; D005998:Glycine / Q000494:pharmacology*; D018684:Glycine Agents / Q000494:pharmacology*; D008070:Lipopolysaccharides; D008297:Male; D008762:Methylhistidines / Q000652:urine; D009752:Nutritional Status / Q000187:drug effects*; D010289:Parenteral Nutrition, Total; D051381:Rats; D017208:Rats, Wistar; D015430:Weight Gain / Q000187:drug effects
D000596:Amino Acids; D018684:Glycine Agents; D008070:Lipopolysaccharides; D008762:Methylhistidines; C482199:lipopolysaccharide, E coli O55-B5; C037998:vintene; D003404:Creatinine; C028118:3-methylhistidine; D005998:Glycine