Meldrum D R, Ayala A, Chaudry I H
Department of Surgery, Michigan State University, East Lansing 48824.
Am J Physiol. 1993 Aug;265(2 Pt 1):C412-21. doi: 10.1152/ajpcell.1993.265.2.C412.
Although diltiazem improves immune responses after hemorrhage and resuscitation, its mechanism remains unknown. To study this, C3H/HeN mice were bled to a mean blood pressure of 35 mmHg, maintained at that level for 1 h, and then adequately resuscitated and treated with diltiazem (400 micrograms/kg body wt) or saline (vehicle). One hour after hemorrhage and resuscitation, splenic microvascular blood flow was determined by laser Doppler flowmetry. Splenocytes were also harvested and ATP levels and cytoplasmic free Ca2+ concentration ([Ca2+]i) were determined by 31P nuclear magnetic resonance and fluo 3 flow cytometry, respectively. Splenocyte functions were determined by measuring interleukin (IL)-1, IL-2, IL-3, IL-6, and tumor necrosis factor concentrations in concanavalin A-stimulated supernatant with cytokine-specific cellular assays. Hemorrhage and resuscitation caused a significant decrease in the splenocyte's ability to release cytokines, which was correlated with significant reductions in splenocyte ATP levels and splenic microvascular blood flow as well as a significant increase in splenocyte [Ca2+]i. Diltiazem significantly decreased splenocyte [Ca2+]i while improving splenocyte ATP levels, cytokine production, and splenic microvascular blood flow. Nitroglycerin (71 micrograms/kg body wt) administration improved splenic microvascular blood flow to diltiazem-treated levels but failed to concomitantly improve splenocyte ATP levels or cytokine production. Thus diltiazem's immunoprotective effects appear to be the result of decreased Ca(2+)-induced splenocyte injury.
尽管地尔硫䓬可改善出血和复苏后的免疫反应，但其机制尚不清楚。为研究此机制，将C3H/HeN小鼠放血至平均血压35 mmHg，维持该水平1小时，然后充分复苏并用 地尔硫䓬（400微克/千克体重）或生理盐水（溶剂）治疗。出血和复苏后1小时，通过激光多普勒血流仪测定脾微血管血流量。还收集脾细胞，分别通过31P核磁共振和荧光素3流式细胞术测定ATP水平和细胞质游离Ca2+浓度（[Ca2+]i）。通过细胞因子特异性细胞测定法测量伴刀豆球蛋白A刺激的上清液中的白细胞介素（IL）-1、IL-2、IL-3、IL-6和肿瘤坏死因子浓度，以确定脾细胞功能。出血和复苏导致脾细胞释放细胞因子的能力显著下降，这与脾细胞ATP水平、脾微血管血流量的显著降低以及脾细胞[Ca2+]i的显著增加相关。地尔硫䓬显著降低脾细胞[Ca2+]i，同时提高脾细胞ATP水平、细胞因子产生和脾微血管血流量。给予硝酸甘油（71微克/千克体重）可使脾微血管血流量改善至地尔硫䓬治疗水平，但未能同时改善脾细胞ATP水平或细胞因子产生。因此，地尔硫䓬的免疫保护作用似乎是Ca(2+)诱导的脾细胞损伤减少的结果。
