Rose S, Pizanis A, Silomon M
University of Saarland, Department of Trauma, Hand and Reconstructive Surgery, Homberg/Saar, Germany.
Hepatology. 1997 Feb;25(2):379-84. doi: 10.1053/jhep.1997.v25.pm0009021950.
The present study evaluated the effect of the benzothiazepine Ca2+ channel blocker diltiazem (DZ) on altered hepatocellular Ca2+ regulation and oxidant injury during hemorrhagic shock/resuscitation. In anesthetized, male Sprague-Dawley rats, hemorrhagic shock was induced by rapid blood withdrawal and maintaining the mean arterial blood pressure at 40 mm Hg over 60 minutes. Rats were then resuscitated with 60% of shed blood and threefold the shed blood volume of Ringer's lactate. At the end of ischemia, and 60 or 300 minutes after resuscitation, hepatocytes were isolated by liver collagenase perfusion. Hepatocellular Ca2+ exchange (Ca2+ex), rate of cellular Ca2+ influx (Ca2+in), and Ca2+ membrane flux (Ca2+flux) were determined using 45Ca incubation techniques. Hepatocyte oxidant injury was evaluated by fluorometrically measuring thiobarbituric acid reactive substances and oxidized/reduced glutathione. Both hemorrhage and hemorrhage/resuscitation increased hepatocellular Ca2+in, Ca2+ex, and Ca2+flux. In contrast to control and sham-operated rats, in vitro stimulation by the Ca2+ agonist epinephrine (100 nmol/L) of hepatocytes from either hemorrhaged or resuscitated rats did not further increase Ca2+in. Administration of DZ (.8 mg/kg) with resuscitation significantly decreased cellular Ca2+ex and Ca2+flux, but did not restore impaired epinephrine-induced Ca2+in. DZ prevented hepatocyte lipid peroxidation and glutathione oxidation. These findings suggest hepatocellular Ca2+ overload and impaired Ca2+ signaling during hemorrhage/resuscitation. Increased Ca2+ uptake could be because of a receptor-gated Ca2+ influx and/or oxygen-free radical induced membrane Ca2+ leaks.
本研究评估了苯并硫氮䓬类钙通道阻滞剂地尔硫䓬（DZ）对失血性休克/复苏期间肝细胞钙调节改变和氧化损伤的影响。在麻醉的雄性Sprague-Dawley大鼠中，通过快速放血诱导失血性休克，并在60分钟内将平均动脉血压维持在40 mmHg。然后用60%的失血量和三倍失血量的乳酸林格液对大鼠进行复苏。在缺血结束时以及复苏后60或300分钟，通过肝胶原酶灌注分离肝细胞。使用45Ca孵育技术测定肝细胞钙交换（Ca2+ex）、细胞钙内流速率（Ca2+in）和钙膜通量（Ca2+flux）。通过荧光法测量硫代巴比妥酸反应性物质以及氧化型/还原型谷胱甘肽来评估肝细胞氧化损伤。出血和出血/复苏均增加了肝细胞的Ca2+in、Ca2+ex和Ca2+flux。与对照和假手术大鼠相比，来自出血或复苏大鼠的肝细胞在体外受到钙激动剂肾上腺素（100 nmol/L）刺激时，Ca2+in并未进一步增加。复苏时给予DZ（0.8 mg/kg）可显著降低细胞Ca2+ex和Ca2+flux，但并未恢复受损的肾上腺素诱导的Ca2+in。DZ可防止肝细胞脂质过氧化和谷胱甘肽氧化。这些发现提示失血性休克/复苏期间肝细胞钙超载和钙信号受损。钙摄取增加可能是由于受体门控钙内流和/或氧自由基诱导的膜钙泄漏。
