异丙酚通过抑制p38激活下调氨处理的大鼠脑星形胶质细胞AQP4的表达并减轻细胞水肿

Propofol attenuates aquaporin-4 over-expression through p38 pathway on ammonia-induced neocortical astrocyte in rats

目的:研究异丙酚对氨处理的大鼠脑皮质星形胶质细胞水通道蛋白-4(AQP4)表达的影响以及相关机制。方法:原代培养Sprague Dawley大鼠大脑皮质星形胶质细胞。用细胞免疫荧光标记星形胶质细胞特异性的神经胶质酸性蛋白,星形胶质细胞纯度达95%以上的细胞备用。实验分为正常对照组(N)、氯化铵(5mmol/L)处理24h组(NH4Cl-24h)、p38抑制剂SB203580(10μmol/L)预处理组(SB)、异丙酚(10μmol/L)预处理组(P)和溶剂二甲亚砜(DMSO)对照组(C)。p38抑制剂、异丙酚和溶剂均预处理星形胶质细胞30min后再加入氯化铵作用24h。用光学显微镜观察各组细胞水肿情况,同时用Western blotting检测AQP4、p38和磷酸化p38的表达情况。结果:光学显微镜观察发现氯化铵处理后星形胶质细胞较正常对照组细胞肿胀明显,异丙酚和p38抑制剂预处理能明显减轻星形胶质细胞水肿。Western blotting检测发现各组星形胶质细胞总p38蛋白表达无明显变化(P>0.05)。异丙酚预处理组和SB预处理组磷酸化p38蛋白和AQP4蛋白表达均较氯化铵处理组和溶剂对照组明显降低(P<0.05)。结论:AQP4蛋白表达受p38信号途径的调节,异丙酚可通过抑制p38信号途径的激活,降低氨引起的星形胶质细胞AQP4蛋白表达上调,减轻细胞水肿。

AIM ： To investigate the effects of propofol on ammonia - induced neoeortical astrocyte aquaporin - 4 expression in rats and its mechanism. METHODS： Astrocytes were separated from newborn Sprague Dawley rats. Glial fibrillary acidic protein, the specific protein of astrocyte, was labeled by cell immunofluorescence method. The purity of astrocyte achieved to 95% was considered to be used in the study. Grouping： cultured astroeytes were randomly divided into 5 groups （n = 3 ） ： normal control group （N） ; ammonia - incubated for 24 h group （ NH4 CI - 24 h ） ; p38 antagonist SB203580 （10 μmol/L） pretreated group （SB）; propofol （10 μmol/L） pretreated group （P）; solvent （DMSO） control group （C）. SB203580, propofol and DMSO were pretreated for 30 min before astrocytes were exposed to NH4Cl. Cell morphology was assessed by light microscopy. The expression of aquaporin - 4 ; p38 and p - p38 were deteeted by Western blotting. RESULTS ： Astrocytes were found significant swelling when exposed to 5 mmol/L NH4 Cl in NH4 Cl - 24 h group compared to control group. Pretreatment with propofol and SB203580 decreased astrocyte swelling. No significant change in total p38 in all groups was observed （ P 〉 0.05 ） by Western blotting analysis, while the levels of p - p38 and AQP4 in group SB and group P were significantly decreased compared to group C and group NH4 Cl - 24 h （ P 〈 0. 05 ）. CONCLUSION： The expression of AQP4 is regulated by p38 pathway. Propofol pretreatment down -regulates aquaporin -4 expression through preventing the ammonia- induced p38 phosphorylation.