|Budget Amount *help
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1992: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1991: ¥1,800,000 (Direct Cost: ¥1,800,000)
The role of physical and functional barrier between the blood and brain is played by endothelial cell layer. There have been few laboratory studies about the effect of hyperthermia to the endothelial barrier integrity. The aim of the present study was to investigate the effect of temperature on endothelial cells and the barrier function. We used endothelial cells isolated from rat brain in our laboratory. In each experiments, endothelial cell monolayers were heated at 42, 43, 44ﾟC for 60 min with water bath. Morphological study of endothelial cells heated at 44ﾟC revealed a lot of cell deaths within 24 hrs. At 43ﾟC, cellular atrophies and microvacuolations were sometimes shown. However, at 42ﾟC, no morphological changes were observed.Survival of heated endothelial cells were investigated by colony forming assays. Heating at 42ﾟC of endothelial cells did not influence cell survival. Over 43ﾟC, survival curve was depressed, depending on temperature and the time of heating. To determine the permeability of endothelial monolayers, we examined a transport of albumin or dextran (M.W.70000) labeled by fluorescein, using double chamber systems.The transport of albumin through endothelial monolayers was increased only by heating at 44ﾟC. However,that of dextran was not changed at any heating conditions. It was considered that gap formations between endothelial cells could explain the increase of albumin transport. Also, the distribution of actins stained by rhodamine-phalloidin in endothelial cells was changed by hyperthermia. At 44ﾟC, almost all actins immediately disappeared. At 43ﾟC, an transient accumulation of actins around the nucleus was observed within 24 hrs after heating. These phenomenon could be considered some cell protective responses, such as heat shock proteins. Our study indicates that endothelial cells are influenced by hyperthermia over 43ﾟC, then, the barrier function is collapsed at 44ﾟC.