COMPLEMENT IN THE REGULATION OF TRANSCELLULAR SODIUM GRADIENT DURING ILLNESS

补体和细胞因子作为细胞内钠离子介质的作用 在危重疾病期间积累和增加的能量需求将是 与中心奖助金的其他成员合作研究 申请。本节中描述的实验基于 补体激活与细胞因子异常产生假说 促进和维持跨膜的潜在致命性改变 钠梯度必然会影响体内的能量代谢 手机。因此，补体激活、细胞因子的产生和 自由基在成因中的变化：1)钠和水的分布 跨细胞膜；2)细胞生物能量学；以及3)细胞内 细胞外的pH值将被检测。在已建立的啮齿动物模型中 脓毒症、脑缺血再灌注损伤，其具体目的是：1) 确定补体激活和细胞因子合成如何影响钠 以及水分分布、Na+-K+-ATPase活性和pH 2)检测补体对小鼠腓肠肌和肝脏的影响。 细胞因子对跨膜钠梯度和继发性钠离子的抑制作用 高能磷酸盐代谢的变化；以及3)与 补体活性和细胞因子分泌作为严重程度的标志 损伤，随着体内磷酸肌酸利用等的变化 作为能量供应变化标志的细胞能量状态指数 以及细胞内的需求。这些关系将在 正常大鼠和大腿(股)腓肠肌的水平 正常、补体缺乏的小鼠的肌肉。钠的变化 水的分布将使用体内的钠磁性进行测量 磁共振波谱(MRS)与位移试剂 三乙烯四胺六醋酸镝(III)和磷的MRS和 MRS-可见的水空间标记二甲基甲基膦和 苯基膦酸根。磷酸肌酸的分解率将是 用活体31P-MRS磁化转移技术测量。 将被用来理解机制的实验干预 观察到的变化包括内毒素和 使用sCR1阻断肿瘤坏死因子和补体。这些活体实验应该 阐明细胞内钠含量增加的机制 在危重疾病期间，提高对疾病调节的认识 细胞生物能量学，并促进制定战略 改善脓毒症和缺血再灌注损伤的作用。

The role of complement and cytokines as mediators of intracellular sodium accumulation and increased energy demand during critical illness will be studied in collaboration with the other members of the center grant application. The experiments described in this section are based on the hypothesis that complement activation and abnormal cytokine production facilitate and maintain potentially lethal alterations in transmembrane sodium gradients that necessarily affect energy metabolism within the cell. Thus, the role of complement activation, cytokine production, and free radicals in the genesis changes in: 1) sodium and water distribution across the cell membrane; 2) cellular bioenergetics; and 3)intracellular and extracellular pH will be examined. In established rodent models of sepsis, and ischemia and reperfusion injury, the specific aims are to: 1) determine how complement activation and cytokine elaboration affect sodium and water distribution, Na+-K+ ATPase activity, and pH in the gastrocnemius muscle and liver; 2) examine the effect of complement and cytokine inhibition on the transmembrane sodium gradient and secondary changes in high energy phosphate metabolism; and 3) correlate changes in complement activity and cytokine elaboration, as markers of the severity of injury, with changes in phosphocreatine utilization and other in vivo indices of cellular energy state as markers of changes in energy supply and demand within the cell. These relationships will be explored in the gastrocnemius muscle and level of normal rats and in the thigh (vastus lateralis) muscle of normal, complement deficient mice. Changes in sodium and water distribution will be measured using in vivo sodium magnetic resonance spectroscopy (MRS) and the shift reagent triethylenetetraminehexaacetate dysprosium (III) and phosphorus MRS and the MRS-visible water space markers dimethylmethylphosphonate and phenylphosphonate respectively. Phosphocreatine breakdown rates will be measured using in vivo 31P-MRS magnetization transfer techniques. Experimental interventions that will be used to understand the mechanisms of the observed changes will include the administration of endotoxin and TNF and complement blockade using sCR1. These in vivo experiments should clarify the mechanisms by which intracellular sodium content increases during critical illness, improve our understanding of the regulation of cellular bioenergetics and facilitate the development of strategies to ameliorate the effects of sepsis and ischemia-reperfusion injury.