脳皮質切片に与えるグリセロールの膨化抑制および代謝改善効果—脳浮腫のin vitroモデルとして

REDUCTION OF SWELLING AND METABOLIC ENHANCEMENT OF RAT CEREBRAL CORTEX BY GLYCEROL IN VITRO

I．はじめに

　脳浮腫あるいはこれに伴う頭蓋内圧亢進は頭蓋内炎症，脳血管障害，頭部外傷，脳腫瘍などによりひきおこされ，これに対する適切な治療はきわめて重要な臨床課題となつている。

　その治療法の一つとして高張液投与があるが，これはWeed＆McKibben^21）が実験的に高張液の頭蓋内圧下降作用を示し，さらに臨床的にはJavid＆Settlage^9）が尿素を試み髄液圧低下作用を認めたのが最初である。高張グリセロール液については経口および静脈内投与のいずれでも，実験的脳浮腫に有効であることがVirnoら^20）により示され，次いでCantore^4）およびMeyer^12）らが臨床に応用しその頭蓋内圧降下作用を報告しているが，現在では副作用としての溶血防ぐために工夫したグリセロール10W／V％，フルクトース5W／V％，NaCl0.9W／V％の混合液が広く用いられている。しかしグリセロールの抗浮腫作用と脳における神経化学的病態をとりあつかつた報告は乏しい。

The rat cerebral cortical slices were incubated at 37℃ in small flasks with oxygenated Gey's balanced salt solution containing various glycerol concent-rations (0, 30, 90, 150, 225 and 300mM). Sub-sequently two kinds of experiments were under-taken; 1) Swelling was measured as the weight change along with the ³H-inulin space determina-tion of the slices. 2) The metabolic effects were studied by means of ¹⁴C-glutamate uptake and ¹⁴CO₂ production by the slices.

The results thus obtained were as follows;

1. The swelling of the cortical slices during incubation (12.4±2.2% at 30min. and 22.1±2.7% at 60min., respectively) was mainly due to enlarge-ment of the inulin space, which was selectively reduced by glycerol administration withought changing the noninulin space. The degree of re-duction of swelling was closely related to the glycerol concentration in the medium.

2. The cortical slices incubated together with 150mM glycerol in the medium showed a statisti-cally significant increase of ¹⁴C-glutamate uptake and ¹⁴CO₂ production as compared with the control which contained no glycerol in the medium (P<0.05).

From the above results it was concluded that glycerol at a proper concentration could not only suppress edema but also enhance metabolic activity of the brain.