氦氖及氬雷射光經腦窗直接照射到大白鼠大腦皮質部，經不同照射時間後，以活體顯微鏡影視觀察照射前或照射後伊文斯藍染劑滲出腦血管藍染腦組織的程度，以及對碳十四甲基葡萄糖攝取量的改變，探討雷射光對血腦障壁之效能及對血腦障壁通透性的影響，並探知其可逆性程度。由實驗知低能量密度（0.8至1.2焦耳／平方分公）的氦氖雷射需時40分鐘始有效開啟血腦障壁，其恢復時間為30分鐘，而先照射後注入伊文斯藍的效果比先注入染料後照射者效果好。對較高能量的氬雷射而言，能量密度在70至100焦耳／平方公分時需照射30秒始為可靠，但照射後60分鐘，血腦障壁始恢復，而先注入染料或先照射對血腦障壁及藍染腦組織無顯著的差異。當射能量強照射時間短比能量低照射時間長者來得有效。氦氖雷射能量密度在0.8焦耳／平方公分以上，照射大腦皮質後對碳十四甲基葡萄糖腦攝取指數比未照射部位的腦組織呈顯著性(P<0.05)增加。氬雷射能量密度在106焦耳／平方公分以上，照射大腦後對碳十四甲基葡萄糖攝取指數比未照射部位的腦組織亦呈顯著性(P<0.05)增高。在光顯微鏡下所見腦血管組織，除皮質分子層與軟腦膜間充滿著藍染料及部份腦實質部滲有藍染外，腦微血管壁無特別顯著的變化。本實驗結果肯定雷射光不管低能量如氦氖雷射或較高能量如氬雷射，若選擇適當的輸出功率及照射時間，確實可開啟血腦障壁，藍染腦組織，而又可逐漸恢復原狀。
Argon and He-Ne Lasers were used to test the effects of the laser energy to the alterations in the blood-brain barrier. Laser radiated cerebral cortex through the cranial window at different exposure time in anesthesized rat. The opening of the blood-brain barrier was examined by checking the degrees of the extravasation of evans blue administrated in femoral vein before or after laser radiation. Cortex staining could be simultaneously observed through the cranial window and evaluated using a videomicroscope during laser radiation. The permeability of the barrier was estimated from the brain uptake of ¹⁴C-O-methyl-glucose. It took 40 mins radiation under low energy density (0.8-1.2 joules/cm²) of He-Ne laser to open the barrier and took another 30 mins after radiation to recover it. Deeper cortex staining was found in the event of administration of evans blue at post-radiation than pre-radiation. In high energy of argon laser (70-100 joules/cm²) 30 sees radiation was required for opening the barrier and more than 60 mins for the recovery. There was no significant difference on the opening of the blood-brain barrier between pre-and post-radiation of argon laser. In general, high energy with short exposure time is more effective than low energy with long duration of exposure. Brain uptake index of ¹⁴C-O-methyl-glucose in the target zone radiated by He-Ne laser was significantly higher than that of intact zone (P<0.05), while the target zone by argon laser was also significantly higher than that of intact zone (P<0.05). Heavy staining was found in the interstitial space between cortical molecular layer and pia mater, and around the parenchyma cells. No obvious change of endothelial wall of microvessels was found under light micropcopte. The results indicate that argon or He-Ne laser with a suitable energy density and exposure time not only can induce the opening of the blood-brain barrier, but also will have a reversible response.
