甘氨酰谷氨酰胺二肽对烧伤大鼠心功能的保护作用

Protective effects of glyeyl-glutamine dipeptide supplement on the heart function in burn rats

目的了解甘氨酰谷氨酰胺二肽(简称甘谷二肽)对严重烧伤大鼠心肌力学功能的保护作用,并探讨其机制。方法将136只Wistar大鼠分成对照组8只(不予烧伤)、烧伤组32只、谷氨酰胺组32只、甘氨酸组32只、甘谷二肽组32只。后4组均造成30%TBSAⅢ度烧伤。5组大鼠依次给予酪氨酸1.5g·kg^(-1)·d^(-1)、酪氨酸1.5 g·kg^(-1)·d^(-1)、谷氨酰胺1.0 g·kg^(-1)·d^(-1)+酪氨酸0.5 g·kg^(-1)·d^(-1)、甘氨酸0.5 g·kg^(-1)·d^(-1)+酪氨酸1.0g·kg^(-1)·d^(-1)、甘谷二肽1.5 g·kg^(-1)·d^(-1)。伤后12、24、48、72 h检测大鼠心肌组织还原型谷胱甘肽(GSH)、腺苷一磷酸(AMP)、腺苷二磷酸(ADP)、腺苷三磷酸(ATP)、细胞能荷(EC)的含量和主动脉收缩压(AOSP)、主动脉舒张压(AODP)及左心室收缩压(LVSP)、左心室压力变化最大上升速率(+dp/dtmax)。结果后4组大鼠伤后心肌组织GSH、ATP和EC含量以及AOSP、AODP、LVSP、+dp/dtmax检测值普遍低于对照组(P<0.01),AMP、ADP含量则普遍高于对照组(P<0.01)。与烧伤组比较,后3组上述指标均有明显改变。伤后12h甘谷二肽组的GSH含量为(72.7±1.7)μmol/g,高于谷氨酰胺组(67.8±3.8)μmol/g(P<0.01);该时相点EC、AOSP的检测值亦高于谷氨酰胺组(P<0.01)。伤后48 h甘谷二肽组GSH、EC、AOSP的检测值高于甘氨酸组(P<0.01)。结论大鼠烧伤后给予谷氨酰胺、甘氨酸和甘谷二肽,能不同程度改善心肌组织GSH、高能磷酸化合物含量,缓解心肌力学功能的下降。甘谷二肽的疗效明显优于谷氨酰胺或甘氨酸,提示它对烧伤后心脏功能的保护作用具有协同效应。

Objective To investigate the protective effects of glyeyl-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 ） , Gin group（ Gin, 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·kg^-1·d^-1）, glutamine （1.0 g·kg^-1·d^-1）and tyrosine（0.5 g ·kg^-1·d^-1）,glyeine（0.5 g·kg^-1·d^-1） and tyrosine（ 1.0 g ·kg^-1·d^-1 ） , and Glycyl-glutamine dipeptide（ 1.5 g·kg^-1·d^-1 ） after receiving a 30% TBSA full-thickness burn on the back. Glutathion（ GSH ） , adenosine monophosphate（AMP） , a- denosine diphosphate （ADP） ,adenosine triphosphate（ATP） ,cell energy charge（EC） and the index of myocardial dynamics （ ASOP, AODP, LVSP, ＋ dp/dtmax） were measured atl2, 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, Gin , 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 ） μmol/g in Gly-Gln group at 12 PBH was obviously higher than that in Gin group （67.8 ± 3.8 ）μmol/g（ P 〈0.01 ）. The levels of EC and AOSP were obviously higher in Gly-Gln group than that in Gin 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 Gin supplementation after bums 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 Gin , indicating that the protective effect on myocardial function after severe burns by Gin and Gly is synergistic.