剪切流场中内皮细胞膜张应力累加效应的实验研究-离体血管段长度与其蛋白质代谢的相关性

用离体血管灌流试验验证冯元桢等关于血管内皮细胞的膜张应力逆血流方向轻加的理论分析。用０．１２Ｎ／ｍ＾２剪应力剪切人脐静脉段内皮细胞２０ｈ后，两种不同长度离体血管的内皮素平均分泌速率无显著差异，但在分泌速率的曲线形态，特征方程和最大分泌速率，最小分泌速率及分泌速率变异系数上差异较大；ＡＴⅡ的平均分泌速率差异彩显著，１１ｃｍ处理比２１ｃｍ处理高６８％。

STUDY ABOUT THE ACCUMULATION EFFECT OF THE TENSILE STRESS ON THE ENDOTHELIAL CELL MEMBRANE UNDER SHEAR FLOW FIELD-CORRELATION OF LENGTH OF VASCULAR SEGMENT IN VITRO WITH PROTEIN METABOLISM BY ENDOTHELIAL CELLS

Experiments of vessels under perfusion stress in vitro were used to verify a theoretical hypothesis proposed by Fung and coworker that the tensile stress could accumulate in the vascular endothelium against the direction of blood flow. After the human umbilical vein segment(HUVS) with length of 11cm and 21 cm were exposed to the same steady laminar shear stress of 1.2dyn/m2 for 20 hours in vitro, the average production rates of endothelin(ET) by endothelial cells of these two different length vein segments did not differ significantly but their curves of ET production versus exposed time were quite different. They differ in the whole curve appearance,the fitted equation, the maximum and minimum points and the coefficients of variation. As for angiotensin II(ATII), which average production rates in two different length vein segments were different significantly. In 11cm length HUVS,the production rate of ATII is 68% higher than that of 21cm(49.43 ± 0.28 vs 29.40 ± 0.86 pg/cm2). When HUVS with 10cm length and 15cm length were exposed to the same steady laminar shear stress of 0.48dyn/cm2 for 24 hours, the average production rates of both ET and AT II were different significantly for these two different length vein segments. The production rate of ET in 10cm. HUVS is 14% lower than that in 15cm length HUVS(30.62 ± 0.49 vs 34.92 ± 0.98 pg/cm2) and the production rate of AT II in 10cm length HUVS is 30% higher than that in 15cm length HUVS(85.30 ± 0.41 vs 67.13 ± 0.28 pg/cm2). Generally speaking, there exits high correlation between the length of HUVS with the protein metabolism of stressed endothelial cells, which suggests that the tensile stress on the endothelial cell membrane could accumulate.