Enhancement of postoperative recovery by preoperative oral co-administration of the amino acids, cystine and theanine, in a mouse surgical model

Abstract

Background & aims: Glutathione (GSH) is important in the control of immune responses, and its levels decline following trauma. We previously reported that the oral administration of cystine/theanine (CT) increased GSH synthesis and that CT intake inhibited intense exercise-induced inflammation. Based on these results, we hypothesised that CT inhibits surgically induced inflammation and promotes postoperative recovery. Our aim was to confirm this hypothesis using a mouse surgical model.

Methods: CT or a vehicle (V) was administered orally to mice once a day for 5 days, until the day of surgery. On the day of surgery, a sham operation or an intestinal manipulation was performed 2 h after the oral administration of CT or V. Levels of IL-6 in the blood and GSH in the intestine were analysed 2 h after surgery. Behavioural analysis was also undertaken after surgery.

Results: Treatment with CT inhibited the manipulation-induced increase in IL-6 in the blood and decrease in GSH in the intestine. There was a significant negative correlation between IL-6 in the blood and GSH in the intestine. In addition, behavioural analysis revealed that CT administration improved locomotor activity and food intake after surgery.

Conclusion: These results suggest that CT suppresses inflammatory responses by inhibiting the surgically induced decrease in GSH in the small intestine and promotes postoperative recovery.