Eizayaga Francisco, Scorticati Camila, Prestifilippo Juan-P, Romay Salvador, Fernandez Maria-A, Castro Jose-L, Lemberg Abraham, Perazzo Juan-C
Laboratory of Portal Hypertension, School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 956, C.P. 1113, Ciudad Autonoma de Buenos Aires, Republica Argentina.
World J Gastroenterol. 2006 Mar 7;12(9):1367-72. doi: 10.3748/wjg.v12.i9.1367.
To study the blood-brain barrier integrity in prehepatic portal hypertensive rats induced by partial portal vein ligation,at 14 and 40 d after ligation when portal pressure is spontaneously normalized.
Adult male Wistar rats were divided into four groups: Group I: Sham14d , sham operated; Group II: PH14d , portal vein stenosis; (both groups were used 14 d after surgery); Group III: Sham40d, Sham operated and Group IV: PH40d Portal vein stenosis (Groups II and IV used 40 d after surgery). Plasma ammonia,plasma and cerebrospinal fluid protein and liver enzymes concentrations were determined. Trypan and Evans blue dyes, systemically injected,were investigated in hippocampus to study blood-brain barrier integrity. Portal pressure was periodically recorded.
Forty days after stricture, portal pressure was normalized, plasma ammonia was moderately high, and both dyes were absent in central nervous system parenchyma. All other parameters were reestablished. When portal pressure was normalized and ammonia level was lowered, but not normal, the altered integrity of blood-brain barrier becomes reestablished.
The impairment of blood-brain barrier and subsequent normalization could be a mechanism involved in hepatic encephalopathy reversibility.Hemodynamic changes and ammonia could trigger blood-brain barrier alterations and its reestablishment.
研究部分门静脉结扎诱导的肝前性门静脉高压大鼠在结扎后14天和40天门静脉压力自发恢复正常时血脑屏障的完整性。
成年雄性Wistar大鼠分为四组：第一组：假手术14天组，行假手术；第二组：门静脉高压14天组，门静脉狭窄；（两组均在术后14天使用）；第三组：假手术40天组，行假手术；第四组：门静脉高压40天组，门静脉狭窄（第二组和第四组在术后40天使用）。测定血浆氨、血浆和脑脊液蛋白以及肝酶浓度。全身注射锥虫蓝和伊文思蓝染料，在海马体中进行研究以评估血脑屏障的完整性。定期记录门静脉压力。
狭窄40天后，门静脉压力恢复正常，血浆氨中度升高，中枢神经系统实质中两种染料均未出现。所有其他参数均恢复正常。当门静脉压力恢复正常且氨水平降低但未恢复正常时，血脑屏障完整性的改变得以恢复。
血脑屏障的损害及其随后的恢复可能是肝性脑病可逆性的一种机制。血流动力学变化和氨可引发血脑屏障改变及其恢复。
