Effects of nitric oxide on microviscosity and polarity of erythrocyte membranes in experiment

Enhancement of methods for protecting target organs during coronary artery bypass surgery determined the development of a technology for delivering nitric oxide (NO) to the systemic blood flow using a cardiopulmonary bypass (CB) apparatus, which makes NO available to all organs and tissues.The aim of the study was to access the effect of perioperative NO conditioning on the coefficients of microviscosity and polarity of sheep etythrocyte membranes during experimental surgical intervention using CB.Material and methods. Study was carried out on 20 sheep weighing 30–34 kg. Two groups were formed. In the CB group, 10 sheep underwent the standard clinical protocol of artificial lung ventilation (ALV) and CB. In the CB + NO group, 10 sheep received NO at a dose of 80 ppm through the circuit of ALV apparatus immediately after tracheal intubation. At the start of CB, NO was delivered to the extracorporeal circulation circuit at a dose of 80 ppm for 90 min. After disconnection from CB, NO supply continued through the ALV apparatus at a dose of 80 ppm for 60 min. The coefficients of microviscosity and polarity of sheep erythrocyte membranes were determined by spectrofluorimetry using pyrene probe.Results and discussion. The implementation of CB was accompanied by a statistically significant decrease in the microviscosity coefficient in the zones of proteinlipid contact of sheep erythrocyte membranes. In the zone of total lipids, the microviscosity coefficient did not change after CB implementation. The membrane polarity coefficient at the final stage of the surgery increased significantly in the zone of annular lipids and did not change in the zone of total lipids. NO supply to the circuit of the extracorporeal circulation neutralizes the revealed increase in the microviscosity and polarity of the annular lipids.Conclusions. The introduction of NO into the extracorporeal circulation circuit at the concentration of 80 ppm prevents a decrease in the coefficients of microviscosity and polarity of annular lipids of erythrocyte membranes that occurs during cardiac surgery.