[Protective effects of glycyl-glutamine dipeptide supplement on the heart function in burn rats].

Objective: To investigate the protective effects of glycyl-glutamine dipeptide supplement on the function of myocardial dynamics in severely burned rats, and to explore its mechanism.

Methods: One hundred and thirty-six Wistar rats were randomly divided into five groups: i. e, control group (C, n = 8, without burns), burn group (B, n = 32), Gln group (Gln, n = 32), Gly group (Gly, n = 32) and Gly-Gln group (Gly-Gln, n = 32). The rats in the latter four groups were respectively treated with tyrosine (1.5 g x kg(-1) x d(-1)), glutamine (1.0 g x kg(-1) x d(-1)) and tyrosine (0.5 g x kg(-1) x d(-1)), glycine (0.5 g x kg(-1) x d(-1)) and tyrosine (1.0 g x kg(-1) x d(-1)), and Glycyl-glutamine dipeptide (1.5 g x kg(-1) x d(-1)) after receiving a 30% TBSA full-thickness burn on the back. Glutathione (GSH), adenosine monophosphate (AMP), adenosine diphosphate (ADP), adenosine triphosphate (ATP), cell energy charge (EC) and the index of myocardial dynamics (ASOP, AODP, LVSP, + dp/dtmax) were measured at 12, 24, 48, 72 post-burn hours (PBH).

Results: The content of GSH, ATP, EC and the level of aortic systolic pressure (ASOP), aortic diastolic blood pressure (AODP), left ventricular end diastolic pressure (LVEDP) and maximum rate of intraventricular pressure rise/down (+ dp/dtmax) in B, Gln, Gly, Gly-Gln groups were obviously lower than those in C group (P < 0.01), while the levels of AMP and ADP showed an opposite tendency. Compared with B group, the above indices were ameliorated. The content of GSH (72.7 +/- 1.7) micromol/g in Gly-Gln group at 12 PBH was obviously higher than that in Gln group (67.8 +/- 3.8) micromol/g (P < 0.01). The levels of EC and AOSP were obviously higher in Gly-Gln group than that in Gln group (P < 0.01). The level of GSH, EC, AOSP in Gly-Gln groups were obviously higher than those in Gly group at 48 PBH.

Conclusion: Glycyl-glutamine dipeptide, Gly and Gln supplementation after burns can improve the content of GSH and high energy phosphate compound, and suppress the decline of myocardial dynamics function. The effects of Glycyl-glutamine dipeptide is better than single Gly or Gln, indicating that the protective effect on myocardial function after severe burns by Gln and Gly is synergistic.