L-arginine improves hemodynamic function and coronary flow in an experimental model of ischemia-reperfusion injury

Ischemia and reperfusion injury decrease the release of nitric oxide by vessels endothelial cells, which influences postischaemic coronary flow and return of left ventricle haemodynamic function. The study was conducted to answer the question how addition of L-arginine in cardioplegic and reperfusion fluids influences nitric oxide release, inducing the coronary flow and postischaemic haemodynamic heart function.

The research was conducted on 56 rats, divided randomly into seven groups: control (C) and six experimental groups (E), where L-arginine was administrated in increasing doses of 0.3, 3.0 and 30.0 mM/L to cardioplegic (E1, E2 and E3 group) or reperfusion solution (E4, E5 and E6 group). To simulate a course of cardiac surgery the following stages of experiment were carried out: initial perfusion on the nonworking and working heart, cardioplegia, cold cardioplegic arrest and reperfusion of the non-working and working heart.

Level of nitric oxide during cardioplegic perfusion decreased in all groups. During reperfusion on non-working and working heart model we noticed the significant increase of nitric oxide for all groups. Along with nitric oxide increase, coronary flow increases, whereas with the decrease of level of nitric oxide, the coronary flow also diminished. During cardioplegic perfusion coronary flow constantly decreased in all groups and during reperfusion we observed the new increase of coronary flow. In groups E1, E2 and E3 the increase of coronary flow was significant.

Obtained data suggest that administration of L-arginine in the preischaemic and in the initial phase of reperfusion stimulates increase in nitric oxide release what is positively correlated with the increase of coronary flow.