大鼠小肠肠系膜微血管血流随温度变化的光学检测

Optical Monitoring of Dynamics of Blood Flow in Locally Heated Microvessels on Intestine Mesentery of Rats

利用 CCD显微成像技术和激光散斑技术 ,对局部加热 (41℃～ 5 4℃ ,30 m in)下大鼠小肠肠系膜微血管的管径 (直径约 15μm～ 5 0μm )和血流速率的变化进行实时、在体监测 ,并由二者计算血流量的变化。结果表明 :4 1℃、4 3℃、4 5℃、4 6℃各温度点 30 min的加热过程中 ,血流速率变化平缓 ,血管管径和血流量明显增加 ,最终均逐渐趋于恒定。4 9℃时 ,血流速率仅在前 12 m in内增加 ,30 min时已降至低于初始值 ;血管管径及血流量在 14 m in时达最大后开始减小 ,加热停止时仍旧高于初始值。温度高于 4 9℃时 (5 1℃、5 4℃ )血流速率、管径、血流量呈现先升高后下降的变化趋势 ,在 30 m in时 ,三者均低于初始值。由此可知 ,加热时间为 30 min,大鼠肠系膜微血管的临界温度为 4 9℃ ;在相同的时间条件下 ,热损伤速率随温度升高而增加。

Abstrast:In this study dynamic change of blood flow in local heated mesentery of intestine of SD rats was measured by utilizing laser speckle measurement(measuring the velocity of blood) and CCD microscopic imaging technique (measuring the diameter of vessels)at seven different temperatures(41℃?43℃?45℃?46℃?49℃?51℃?54℃)for 30 minutes respectively in vivo and real time.The results showed that while heated at 41℃～46℃ for 30 min,velocity increased slightly but diameter and blood flow increased markedly and finally got to constants.The value of velocity increased to maximum when microvessels were heated with 49℃ for 12 min.At this temperature,diameter and blood flow increased during the first 14 min,but began to decrease when heated longer.When temperature is higher than 49℃ (51℃,54℃),velocity,diameter and blood flow all increased at first and then decreased during 30 min and at the end of heating they were all greatly lower than control value.We draw our conclusion that the critical temperature is 49℃ for intestine microcirculation with heating for 30 min.And the rates of thermal damage are proportion to temperature for the same heating time.