重组水蛭素经蟾蜍肺泡膜的转运研究

 目的考察重组水蛭素跨膜转运的基本特点和影响因素,对转运的机制进行初步的探讨,为重组水蛭素肺部给药的体内评价打下理论基础。方法将蟾蜍肺泡膜作为肺液上皮体外模型,装在水平扩散池上,向给药池中加入荧光标记的重组水蛭素(FTTC-rHV₂),在不同的温度、不同的给药池初始浓度、不同的转运方向的条件下测定表观渗透系数,同时考察给药池溶液中高渗透压、酸性pH、加入渗透促进剂或者代谢抑制剂时的转运情况。同时监测膜电阻的变化。结果FTTC-rHV₂的表观渗透系数具有浓度非依赖性、温度非依赖性和方向非依赖性。酸性pH环境、高渗透压和吸收促进剂使表现渗透系数明显增加,而代谢抑制剂对袁观渗透系数没有明显的影响。3h内膜电阻没有明显的变化,说明膜的完整性得以保持。结论重组水蛭素经蟾蜍肺泡膜的转运是一个非能量依赖、非载体依赖的被动扩散过程。

Transport of recombinant hirudin across xenopus pulmonary membrane

OBJECTIVE To investigate the transport profile of recombinant hirudin across xenopus pulmonary membrane and examine the factors influencing the transport, in order to attain primary knowledge on the transport mechanism of hirudin across alveolar epithelium. METHODS Xenopus pulmonary membrane was mounted on the horizontal diffusion cell and the solutions containing fluorescence-labeled recombinant hirudin (FTTC-rHV2) were added into the donor chamber. Apparent permeability coefficients for different temperature, different donor concentration and opposite direction were determined. The effect of high osmotic pressure, acidic pH, absorption enhancer and metabolic inhibitor was also examined. In addition, the resistance of the tissue was monitored during the experimental period.RESULTS Apparent permeability coefficient of FTTC-rHV2 was found to be concentration-independent, temperature-independent, direction-independent and energy-independent, whereas acidic pH, high osmotic pressure and absorption enhancer significantly increased the apparent permeability coefficient.The resistance of the tissue remained unchanged for 3 h, suggesting the maintenance of the integrity of pulmonary epithelium. CONCLUSION The transport of recombinant hirudin across xenopus pulmonary membrane was a passive diffusion process which was energy-independent and carrier-independent.