- 作者: 顏茂雄; 李素華
- 作者服務機構: 國防醫學院藥理學科
- 中文摘要:
本研究以冷凍損傷技術引起老鼠腦水腫模式,觀察Dexamethasone對125I-白蛋白(RISA)及14C-氨基異丙酸(AIB)
在血一腦分佈之影響。本實驗共分成兩大組(未治療組與Dexamethasone治療組),每組老鼠在皮質局部凍傷後不同時間
(即刻或1天),分別由靜脈注射125I-RISA或14C-AIB。AIB實驗時間為十分鐘,而RISA實驗時間分別為30分或4小
時。AIB或RISA在局部腦組織之分佈以自動放射顯影定量技術測定。本實驗結果顯示,Dexamethasone無影響AIB在
十分鐘與RISA在30分實驗過程中,兩者分別在腦部受傷部位與未損傷部位附近組織之分佈。然而,Dexamethasone卻
很明顯減少RISA在4小時實驗過程中由受傷部位轉移至未受傷部位組織。由以上結果認為Dexamethasone之所以能改
善腦水腫之可能作用機轉並非以往假設認為其具有修補或穩定受傷之腦血管。本實驗結果認為由於Dexamethasone具改
變受傷附近組織腦細胞外液空間結構而導致液體或溶質由受傷部位流經?近組織細胞間液阻力增加所致。體 - 英文摘要: The effects of dexamethasone (Dex) on the blood-brain distribution of 14C-alpha-aminoisobutyricacid (AIB) and 125I-albumin (RISA) was studied in the rat freeze-lesion model of cerebral edema. Untreat-ed and Dex-treated rats were studied by intravenously administering either AIB or RISA immediately afteror one day after localized cortical freezing. The AIB experiments were terminated after 10 min; the RISAexperiments were terminated after 30 min or 4 hr. Local tissue distribution of AIB and RISA was assessedby quantitative autoradiography. The distribution of both RISA and AIB within the lesion was unaffectedby Dex. In the tissue around the lesion, Dex did not alter the distribution of AIB in the 10 min experi-ments or of RISA in the 30 min experiments. Dex did, however, diminish the movement of RISA into theadjacent tissue during the 4-hr experiments. The intralesional AIB and RISA distribution data plus theperilesional 10-min AIB and 30-min RISA distribution data indicate that Dex does not act by reducing theflow of solutes and water across damaged or leaky vessels in and around the lesion. The 4-hr RISA datasuggests that Dex alters the structure of the extracellular space in the tissue around the lesion (especiallyin the white matter) and thereby increases the resistance of the interstitium to the flow of solutes and fluidfrom the lesion into the adjacent tissue.
- 中文關鍵字: cerebral edema; dexamethasone; radiolabeled albumin; alpha-aminoisobutyric acid; interstitial bulk flow
- 英文關鍵字: --