L-精氨酸对深低温停循环脑血流及代谢的影响

Influence of L-arginine on regional cerebral blood flow and cerebral metabolic recovery after deep hypothermic circulatory arrest

目的 通过深低温停循环 (DHCA)转流模型 ,研究L 精氨酸 (L arg)在低温缺血时对脑血流和代谢的影响。方法 采用 3～ 4周龄上海种白猪 ,按临床方法建立体外循环。于转流前、降温 5min、降温末、复温 5min、复温末、常温 6 0min、转流结束等时间点分别测定颈动脉流量、颈内静脉一氧化氮和乳酸含量、脑氧代谢率、脑皮质ATP及一氧化氮合酶活性。结果 L arg能增加脑血流量和加快停循环后脑组织ATP、颈内静脉乳酸含量的恢复 ;L 硝基 精氨酸甲酯 (L NAME)却使脑血流量降低和减慢停循环后脑组织ATP及颈内静脉乳酸含量的恢复。结论 在DHCA时应用L arg具有较好的脑保护作用 ;而应用L NAME具有脑损害作用。

Objective The aim of this study was to investigate the protective effects of L arginine (L arg), the precursor of nitric oxide on regional cerebral blood flow and cerebral metabolic recovery after deep hypothermic circulatory arrest. Methods After cardiopulmonary bypass was established using fifty 3～4 week old piglets. Carotid artery blood flow (CarBF), intrajugular nitric oxide and lactate content, cerebral oxygen metabolic rate, cortical adenosine triphosphate (ATP) and nitric oxide synthase activity were measured before institution of CPB, 5 minites after cooling, end of cooling, 5 minites after rewarming, end of rewarming, 60 minites of normothemic perfusion, and cessation of CPB. Results L arg increased nitric oxide generation, CarBF, recovery of cerebral ATP and intrajugular lactate content; L nitro arginine methyl ester (L NAME) inhibited production of nitric oxide, reduced CarBF and recovery of cerebral ATP, intrajugular lactate content. Conclusion In a piglet model of deep hypothermic circulatory arrest, L arg has a beneficial effect and L NAME has a deleterious effect on regional cerebral blood flow and metabolic recovery.