Effects of dexmedetomidine on pneumonocyte apoptosis and CCAAT/enhancer binding protein homologous protein in acute lung injury induced by ischemia/reperfusion during liver transplantation in rats
10.3969/j.issn.1008-9691.2015.03.009
- VernacularTitle:右美托咪定对大鼠移植肝缺血/再灌注所致急性肺损伤中细胞凋亡及CCAAT增强子结合蛋白同源蛋白的影响
- Author:
Limei CHU
;
Guanghui YANG
;
Lijuan DONG
;
Hongjie LYU
;
Xuemin WU
;
Hui QIAO
- Publication Type:Journal Article
- Keywords:
Dexmedetomidine;
CCAAT/enhancer binding protein homologous protein;
Apoptosis;
Acute lung injury;
Liver transplantation;
Liver ischemia/reperfusion
- From:
Chinese Journal of Integrated Traditional and Western Medicine in Intensive and Critical Care
2015;22(3):262-266
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effects of dexmedetomidine pre-treatment on pneumonocyte apoptosis and CCAAT/enhancer binding protein homologous protein (CHOP) in acute lung injury (ALI) induced by ischemia/reperfusion (I/R) during orthotopic liver transplantation in rats.Methods Forty adult male Sprague-Dawley (SD) rats were randomly divided into four groups by random number table method: sham operation group, I/R model group, dexmedetomidine low dose group and dexmedetomidine high dose group, 10 rats per group. Hepatic artery was ligated and cut off by two cuff method, and the portal vein was completely opened after donor liver transplanted into the recipient, thus, a hepatic I/R model was established. The perihepatic ligaments of rats were just separated after laparotomy in sham operation group and no other special treatment was performed. One hour prior to I/R, dexmedetomidine at a dose of 2.5μg·kg-1·h-1 and 5.0μg·kg-1·h-1, respectively, were pumped intravenously and finished within 1 hour in the rats of low dose group and high dose group. After experiment, the lung tissue was taken, and the lung wet/dry weight (W/D) ratio was determined. Pathological changes of lung tissue were observed and alveolar damage index of quantitative assessment (IQA) was tested by light microscope, and changes of ultrastructure of lung tissue were observed by transmission electron microscope. The mRNA and protein expressions of CHOP were detected respectively by reverse transcription-polymerase chain reaction (RT-PCR) and Western Blot. The apoptosis in lung tissue was determined by terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) method and apoptosis index (AI) was calculated.Results Compared to sham operation group, the lung W/D ratio (4.94±0.84 vs. 2.29±0.54), IQA [(40.52±5.15)% vs. (4.55±1.85)%] and AI [(36.57±5.85)% vs. (2.85±0.95)%] in I/R model group were significantly higher (allP < 0.01); remarkable injury of lung tissue was confirmed by light microscope and transmission electron microscope in the I/R model group. Compared to I/R model group, the W/D ratio (3.29±0.85, 2.68±0.78 vs. 4.94±0.84), IQA [(23.69±2.62)%, (15.86±3.61)% vs. (40.52±5.15)%] and AI [(25.73±3.71)%, (14.66±2.61)% vs. (36.57±5.85)%] in dexmedetomidine low and high dose groups were markedly lower (allP < 0.01); under light and transmission electron microscopes, the injury of lung tissue in these two dose groups was notably alleviated. There was a large amount of apoptotic cells of pulmonary vascular endothelium and alveolar epithelium in I/R model group, while the cell apoptosis was distinctly decreased in dexmedetomidine low and high dose groups compared to that in model group. Compared to sham operation group, the expressions of CHOP mRNA [absorbance (A) value: 0.96±0.18 vs. 0.43±0.08] and protein (gray scale: 2.79±0.74 vs. 1.02±0.27) were significantly higher in I/R model group (bothP < 0.01). Compared to I/R model group, the expressions of CHOP mRNA (A value: 0.69±0.13, 0.56±0.12 vs. 0.96±0.18) and protein (gray scale: 1.96±0.58, 1.34±0.49 vs. 2.79±0.74) were significantly lower in dexmedetomidine low and high dose groups, the decrease in dexmedetomidine high dose group being more marked (allP < 0.01).Conclusion The pretreatment of dexmedetomidine can protect lung tissue against I/R injury during liver transplantation in rats, and the mechanism may be related to the suppression of CHOP activation and alleviation of lung tissue cell apoptosis.
