开颅手术对大鼠血脑屏障的影响

Effect of craniotomy on blood-brain barrier in rats

目的通过切开硬脑膜和蛛网膜与不切开硬脑膜的开颅手术分析大分子物质是否会进入腑脊液和脑实质内。方法将成年雄性SD大鼠采用随机数字表法分成3组，分别为实验组A、实验组B和对照组C。A组在全身麻醉下行开颅手术，剪开硬脑膜和蛛网膜；B组仅做硬脑膜外的开颅手术；C组只麻醉，不做开颅手术。使用伊文思蓝作为示踪剂来检测实验结果，分别于不同时间点（1，3，6，12，24，72h、1周）之前0．5h内通过静脉注射一定剂量的伊文思蓝，0．5h后处死，收取脑标本。采用荧光分光光度计测量脑组织中伊文思蓝的含量，分别进行统计学处理。对照组除未做开颅手术外，其他处理同实验组。取一部分A组和B组大鼠分别于术前和术后3，72h进行脑组织含水量测定。结果脑组织取材时可见A组1，3，6，12，24h局部呈浅蓝色，72h脑组织的浅蓝色较微弱，1周未发现蓝染。B组和C组局部脑组织未发现蓝染。A组术后1，3，6，12，24，72h和1周脑组织中伊文思蓝的含量[（18．07±1．25）μg/ml、（36．21±0．78）μg／ml、（25．73±1．14）μg／ml、（16．53±0．84）μg／ml、（23．34±1．91）μg／ml、（43．34±2．25）μg／ml、（25．27±1．88）μg／ml]均比B组[（3．15±0．45）μg／ml、（3．36±0．33）μg/ml、（2．98±0．54）μg／ml、（3．47±0．55）μg/ml、（3．54±0．37）μg/ml、（2．88±0．42）μg／ml、（2．85±0．22）μg／ml]和C组（（2．97±0．37）μg/ml]高（P〈0．01）。利用干湿重法进行术前、后脑组织含水量测定，结果显示术前后脑组织含水量改变差异无统计学意义（P〉0．05）。结论开颅术后一些大分子物质能通过头皮创面渗出，在硬脑膜缝合不十分严密的情况下，能越过血脑屏障和血脑脊液屏障直接进入蛛网膜下腔，并进入脑组织内。

Objective To investigate whether the maeromolecular materials could enter eerebrospinal fluid and brain tissues in craniotomy with incision or non-lncision of dura and arachnoid. Methods Adult male SD rats were randomly divided into three groups according to the random number table. The dura and araehnoid of rats in group A were cut open during eraniolomy after general anesthesia; epi- dural craniotomy was done in rats in group B after general anesthesia; rats in group C （ control group） were only generally anesthetized. All the rats were injected with Evans blue, a tracer used to detect the results, half an hour before each time point （1, 3, 6, 12, 24, 72 hours and 1 week） via vein. The rats were executed at each time point to obtain the specimens of brain. The content of Evans blue in brain tissue was measured by fluorescence spectrophotometer for statistical analysis. The water content in the brain tissue was measured,in a part of rats selected in groups A and B preoperatively and at postoperative 3 and 27 hours. Results It was found that some regions of the brain tissue were stained light blue in group A at 1, 3,6 and 24 hours. The blue was much lighter in brain tissue obtained at 72 hours in group A, and no blue stained at 1 week in group A . The contents of Evans blue in the brain tissues of rats in group A at 1 , 3, 6, 12, 24, 72 hours and 1 week were （18.07 ± 1.25）μg/ml, （36.21 ±0.78） μg/ml, （25.73 ± 1.14 ） μg/ml, （ 16.53 ±0.84 ） μg/ml, （ 23.34 ± 1.91 ） μg/ml, （43.34 ± 2.25 ） μg/ml and （25.27 ±1. 88 ）μg/ml respectively, which were significantly higher than （3. 15 ± 0.45 ）μg/ml, （ 3.36 ± 0.33 ） μg/ml, （2.98 ± 0.54） μg/ml, （ 3.47 ± 0.55 ） μg/ml, （ 3.54 ± 0. 37 ） μg/ml, （ 2.88 ± 0.42 ）μg/ml and （2.85 ±0.22 ）μg/ml respectively in group B and （2.97 ± 0.37 ）μg/ml in group C （P 〈 0.01 ）. There was no significant difference in water content in brain tissue before and after operation （ P 〉 0.05 ）. Conclusion After craniotomy with incision of dura and arachnoid, some macromolecular materials can enter the subarachnoid space and the brain parenchyma through blood-brain barrier of the wound of the scalp if the dura is sutured loosely.