流体切应力对中性粒细胞内Ca^(2+)的影响  

EFFECT OF FLUID SHEAR STRESS ON NEUTROPHILS CYTOSOLIC FREE Ca^(2+)

作　　者：田卫[1] 陈槐卿[1] 黄勋[2] 乔小蓉[2] 韩君[1] 陈锐[1] 

机构地区：[1]华西医科大学生物医学工程研究室,成都610041 [2]华西医科大学分析测试中心,成都610041

出　　处：《中国生物医学工程学报》2002年第2期138-143,共6页Chinese Journal of Biomedical Engineering

基　　金：国家自然科学基金重点资助项目 ( 39830 0 110 )

摘　　要：流体切应力是中性粒细胞的重要功能环境 ,但以往的研究很少涉及力学作用对中性粒细胞的影响。我们利用旋转粘度仪提供的流体切应力作用于分离的中性粒细胞 ,采用Fura 2 /AM与细胞内游离Ca2 + 结合 ,检测其荧光强度 ,研究不同力学条件下细胞内游离Ca2 + 浓度的变化情况 ;另外 ,分别以f MLP和TNF两种刺激因子作用中性粒细胞 ,使之激活 ,与此同时考察流体力学作用对中性粒细胞激活程度的影响。结果显示 :定常剪切流 ,切变率由低变高时 ,中性粒细胞内的游离Ca2 + 水平先是显著下降 ,切变率达到一定程度后 ,[Ca2 + ]i逐渐回升 ,并且会超过静止时的水平 ;两种刺激因子在静态下激活中性粒细胞均可使游离Ca2 + 大幅度上升 ,同时给予定常流作用 ,在较低切变率作用下 ,这一上升被明显抑制 ,当切变率升高到一定程度后 ,[Ca2 + ]i回复到静态激活水平甚至更高。正弦振荡剪切作用于中性粒细胞 ,[Ca2 + ]i随最大切变率增大而升高 ,当激活剂和剪切流同时作用时 ,[Ca2 + ]i随最大切变率升高而下降 ,逐渐接近最大切变率相同时的单纯振荡切应力作用的水平。由此我们认为 :体内不同血流环境将影响中性粒细胞的 [Ca2 + ]i,在不同循环部位的血管血流中 ,流体切应力对中性粒细胞的 [Ca2 + ]i有着不同的调节作用。Neutrophils circulate with blood around the body and play an important role in defensive function. In the continuously changing fluid shear stress, the cells perceive various physiological and/or pathological conditions and make corresponding reactions. Fluid shear is an essential functional environment for neutrophils. Previous researches had paid little attention to the direct effects of shear stress on neutrophils. We used rotation viscometer to provide different fluid shear stress fields to separated human neutrophils in calcium free medium and Fura-2/AM was used to detect the concentration of cytosolic free Ca 2+ . Results showed that, in steady laminar shear stress field, with the shear rate changing from low (～6s -1 ) to high (600s -1 ), the [Ca 2+ ]i decreases significantly first and then increases gradually to a level higher than that of static state. Both fMLP and TNFα could increase [Ca 2+ ]i to a much higher level. But when these two stimulants were applied simultaneously with shear stress, the increase in [Ca 2+ ]i at lower shear rates was inhibited; while at higher shear rates, it returned to the level at static state. [Ca 2+ ]i of neutophils increased with increasing maximal shear rate under sinusoidal-oscillatory fluid shear rate. When the stimulants and the sinusoidal-oscillatory fluid shear stress acted on the neutrophils simultaneously, [Ca 2+ ]i decreased with increasing maximal shear rate, and gradually approximated the level of that of the oscillatory shear stress alone at the same maximal shear stress. The results suggest that different blood flow conditions in circulation influence [Ca 2+ ]i of neutrophils in some way and fluid shear stress acts as a regulator of neutrophils in blood flow with different transduction pathways and effects comparable to cytokines or chemoattractants.

关 键 词：流体切应力 中性粒细胞 钙 

分 类 号：R318.01[医药卫生—生物医学工程] R329.27[医药卫生—基础医学]