摘要
目的观察局部亚低温对大鼠自体血注入法脑出血模型水通道蛋白4(AQP-4)mRNA及蛋白质表达的影响,探讨局部亚低温减轻脑出血后水肿的可能机制。方法雄性W istar大鼠240只,随机分为脑出血(ICH)组和脑出血加局部亚低温(ICH+H)组。每组分为对照、脑出血后6、24、72 h,5、7 d共6个亚组,ICH+H组于注血后给予4 h的局部亚低温治疗,各亚组分别进行血脑屏障(BBB)通透性、脑水含量的检测以及应用逆转录(RT)-PCR及W estern印迹对AQP-4进行测定。结果ICH组大鼠脑组织水含量、BBB通透性以及AQP-4 mRNA表达的增加始于脑出血后6 h,AQP-4蛋白质表达的增加始于脑出血后24 h,均至72 h达高峰(P<0.01)。AQP-4 mRNA及蛋白质表达的变化与BBB通透性的变化呈正相关(r=0.78和r=0.76)。ICH+H组的脑组织水含量和BBB通透性在各时间点与ICH组相比明显下降,而AQP-4 mRNA吸光度值(A)在脑出血后48 h与ICH组相比开始较低,在72 h,由ICH组的1.25±0.03降至1.04±0.02(P<0.01),AQP-4蛋白质A值在各时间点与ICH组相比明显下降,在72 h,由ICH组的0.77±0.08下降至0.25±0.04(P<0.01)。结论脑出血后BBB完整性的破坏可以导致AQP-4表达的上升。局部亚低温可以抑制脑出血后AQP-4 mRNA和蛋白质表达的增加。局部亚低温可能既通过减轻BBB完整性的破坏在转录水平抑制AQP-4 mRNA表达的增加,也可以在翻译水平直接抑制AQP-4蛋白质的表达,来减轻脑出血后的脑水肿形成。
Objective To examined the effect of local mild hypothennia on the expression of aquaporin-4（AQP-4） following intracerebral hemorrhage （ICH） in rats and clarified the mechanism of hypothennia on brain edema formation following ICH. Methods Two hundreds and forty male Wistar rats were randomly divided into two groups： the intracerebral hemorrhage （ICH） group, in which autologous arterial blood were stereotaxically injected into right caudate nucleus; the local mild hypothennia（ ICH ＋ H） group, in which the rats were given 4 h local mild hypothennia after the injection of blood. Each group was divided into 6 subgroups： control, 6 h, 24 h, 72 h, 5 d and 7 d after operation; Brain water content was determined by dry-wet weight method and the permeability of BBB was measured by Evans-Blue extravasation. RT-PCR and Western blot were respectively used to evaluate AQP-4 mRNA and protein expression. Results In ICH group, compared with control, ICH significantly increased BWC, the permeability of BBBand the expression of AQP-4 mRNA ,all began at 6 h and peaked at 72 h（P 〈0.01 ）, the increased protein expression of AQP-4 began at 24 h and also peaked at 72 h （ P 〈 0. 01 ）. AQP-4 expression positively correlated, both at the mRNA and the protein level, with the permeability of BBB （ r = 0.78 and r =0.76 respectively）. In ICH ＋H group, compared with ICH group, the elevation of BWC,BBB permeabilityand AQP-4 protein expression were strongly attenuated at all time point by hypothennia treatment （P〈0.01）, while AQP-4 mRNA levels demonstrated a modest attenuation from 48 h. At 72 h, AQP-4 mRNA optical density （A） decreased from 1.25 ± 0. 03 （ ICH group） to 1.04 ± 0.02 （ P 〈 0.01 ）, AQP-4 protein expression （ A ） decreased from 0.77 ±0.08 （ ICH group） to 0.25 ± 0.04 （ P 〈 0.01 ）. Conclusions This study indicates that BBB breakdown can increase the expression of AQP-4 ; local mild hypothermia can significantly reduce brain edema formation after ICH by suppressing the elevation of AQP-4 protein expression; Inhibition of BBB breakdown and the elevation of AQP-4 protein expression with local mild hypothermia appear to contribute to brain protection in this model.
出处
《中华医学杂志》
CAS
CSCD
北大核心
2006年第13期906-910,共5页
National Medical Journal of China
关键词
低温
脑出血
水孔蛋白类
Hypothermia
Cerebral hemorrhage
Aquaporins
