流体切应力作用下中性粒细胞F-肌动蛋白的变化  

Changes of F-actin in Neutrophils under Fluid Shear Stress

作　　者：田卫[1] 陈槐卿[1] 陈蕴颖[1] 雷松[2] 陈云爽[1] 步宏 魏于全[2] 

机构地区：[1]华西医科大学生物医学工程研究室,成都610041 [2]华西医科大学附属第一医院肿瘤生物治疗中心,成都610041 [3]华西医科大附属第一医院移植免疫实验室,成都610041

出　　处：《生物医学工程学杂志》1999年第4期399-405,共7页Journal of Biomedical Engineering

基　　金：国家自然科学基金重点资助!项目(39830110)

摘　　要：中性粒细胞担负着机体的防御功能，其生理特点关系着功能实现。由于中性粒细胞的成熟储存与功能发挥是在不同的力学环境中完成的，因而也就存在着不同的环境适应。Ｆ－ａｃｔｉｎ 的含量与细胞的力学性质有着密切关系。通过对不同切应力下Ｆ－ａｃｔｉｎ 含量及分布的观察，我们发现：在低切应力范围内随着切应力的升高Ｆ－ａｃｔｉｎ 的含量下降，不同的剪切类型所产生的效果有所差异；切应力与ｆ－ＭＬＰ或ＴＮＦ联合作用会使Ｆ－ａｃｔｉｎ 的含量比ｆ－ＭＬＰ或ＴＮＦ单独作用时下降，其趋势与单纯切应力作用相似。切应力作用后，细胞膜附近的Ｆ－ａｃｔｉｎ 明显减少。ｆ－ＭＬＰ或ＴＮＦ使Ｆ－ａｃｔｉｎ 含量升高则主要集中在细胞边缘，这时再施加切应力，细胞边缘的Ｆ－ａｃｔｉｎ 含量也会显著下降。结果表明：中性粒细胞在流体切应力作用下通过Ｆ－ａｃｔｉｎ 的解聚，降低细胞膜附近的硬度，增加细胞的变形能力，从而减少细胞在流体中的阻力，有利于细胞更好地通过循环，完成其功能。当切应力上升到较大值后，细胞内Ｆ－ａｃｔｉｎ 含量会上升，以抵抗力学的破坏作用。可以得出的结论是：切应力作用下，中性粒细胞内Ｆ－ａｃｔｉｎ 含量随所受切应力的大小呈现双向调节，表现出灵活的力学适?Neutrophils are the main defender in the body, and their physiological characters are associated with functions. Because the environments of neutrophils maturation and storage are different from their function environment, they have to adapt thess changes. Filamentous actin (F actin), as one of the important cytoskeleton components of neutrophils, has different quantity and distribution under different physiological conditions. Previous researches are all focused on static activation of neutrophils using various stimulants such as formyl methionyl leucyl phenylalanine (f MLP) and tumor necrosis factor(TNF). In our study, Low Shear 30 and NXE 1 rheometers were used to provide steady or sinu soidaloscillatory fluid shear stress on separated neutrophils. Fluorescent agent Tritc Phalloidin was added to label F actin and the mean fluorescent intensity tested by flow cytometry was used as the indication of F actin quantity and confocal laser scan microscope was used to detect the distribution of F actin in neutrophils. We found that F actin polymerization was significantly decreased under both steady and sinusoidal oscillatory shear stress when the shear stress was below certain level. The density of the cortex F actin near cell membrane in cells sheared became thinner than in that without shear stress. f MLP and TNF both could increase actin polymerization in neutophils due to activation. When neutorphils were activated with f MLP or TNF under shear stress, the quantity of F actin in the cells was also decreased, but it was still higher than that in the cells absent of f MLP or TNF. We concluded that neutrophils had different mechanical properties in different fluid environments. F actin content and distribution would change according to the shear stress values to play their determinant role in neutrophils mechanical adaptation. The mechanism of actin polymerization in neutrophils for mechanical action is probably different from that for chemoattractants and cytokine activation.

关 键 词：中性粒细胞 F-ACTIN 稳定剪切 正弦振荡剪切 

分 类 号：R392.12[医药卫生—免疫学] R318.01[医药卫生—基础医学]