Objective To evaluate the effects of supplementation of glutamine （GLN） on maintaining glutathione （GSH） level

immune system function

liver function

and clinical outcome of patients receiving abdominal operation. Methods Forty patients undergoing elective abdominal surgical treatment were randomly divided into 2 groups: study group （n=20） and control group （n=20）. All patients received total parenteral nutrition （TPN） for up to 7 days during perioperative period. The study group received TPN supplemented with GLN dipeptide while the control group received TPN without GLN dipeptide. Patients in both groups received equivalent nitrogen and caloric intake. Blood sample was taken on preoperative day

and the 1st

3rd

6th postoperative day to measure GSH level

immune indexes

and liver function indexes. Results The decrease of GSH level in plasma and red blood cell （RBC） in study group was less than that in control group during postoperative period. Ratio of GSH/glutathione disulfide （GSSG） in plasma in study group was higher than that in control group on the 3rd postoperative day （52.53±11.46 vs. 31.43±7.27

P=0.001）. Albumin level in study group was higher than that in control group on the 3rd postoperative day （37.7±3.8g/L vs. 33.8±4.2g/P=0.02）. There was no significant difference in the levels of immunoglobin （IgG

IgM

IgA） or T lymphocyte subgroup （CD4

CD8

CD4/CD8） in both groups during postoperative period. There was one case with infectious complication in control group

while none in study group. A trend of shortened hospital stay was observed in study group compared with control group （22.3± 2.1d vs.24.9±1.7d

P=0.32）. Conclusions Supplementation of GLN-enriched TPN has beneficial effects on maintaining GSH levels in plasma and RBC

sustaining GSH/GSSG ratio and albumin level

and keeping antioxidant abilities during postoperative period in patients with abdominal operation

with the trends of decreasing incidence of infectious complication and shortening hospital stay.