大鼠肠缺血再灌注时肺组织β-防御素-2mRNA表达的变化

Changes in β-defensin-2 mRNA expression in the lung tissue after intestinal ischemia-reperfusion in rats

目的观察大鼠肠缺血再灌注时肺组织β-防御素-2（BD-2）mRNA表达的变化。方法72只雄性SD大鼠随机分为2组（n=36）：假手术组（S组）和肠缺血再灌注组（II／R组）。采用夹闭肠系膜上动脉（SMA）的方法制备肠缺血再灌注模型。II／R组阻断SMA1h后再灌注，S组仅分离SMA。分别于再灌注即刻（T0）、再灌注15（T1）、30（R）、60min（T1）、3h（T4）和6h（T5）时处死6只大鼠，取肺组织，光镜下观察肺组织病理学结果，计算肺通透性指数（PPI），检测肺组织肿瘤坏死因子-α（TNF—α）含量和BD-2 mRNA表达水平。结果S组肺组织结构未见异常，II／R组出现肺水肿和中性粒细胞浸润。与S组比较，II／R组再灌注各时点PPI升高，BD-2 mRNA表达上调，L03-时TNF-α含量升高（P〈0．05或0．01）。II／R组BD-2 mRNA表达水平与TNF—α含量及PPI的相关系数分别为0．823和-0．615（P〈0．01）。结论大鼠肠缺血再灌注时肺组织BD-2基因表达上调。

Objective To investigate the effects of intestinal ischemia-reperfusion （II/R） on the β-defensin-2 mRNA expression in the lung tissue in rats. Methods Seventy-two male SD rats weighing 250-300 g were randomly allocated to one of 2 groups （n = 36 each）： group Ⅰ sham operation （S） and group Ⅱ II/R. Intestinal I/R was produced by occlusion of superior mesenteric artery （SMA） for 60 min followed by reperfusion. Six animals were killed at each of the following time points： the onset of reperfusion （T0）, 15, 30, 60 min （T1,2,3 ） and 3, 6 h （T4,5 ） of reperfusion in each group. Lung tissue specimens and broncho-alveolar lavage fluid （BALF） were obtained for microscopic examination and determination of pulmonary permeability index （PPI）, TNF-α content and BD-2 mRNA expression （by RT-PCR）. Results Microscopic examination showed edema and PMN infiltration in the lung in group II/R. The PPI and BD-2 mRNA expression were significantly higher in group II/R than in group S. The TNF-α content was significantly higher at To 3 in group II/R than in group S （ P 〈 0.05 or 0.01）. The BD-2 mRNA expression was positively correlated to the TNF-α content （ r = 0.823, P 〈 0.01） and negatively correlated to PPI （ r = - 0. 615, P 〈 0.05 ）. Conclusion BD-2 gene expression in the lung tissue is up-regulated after intestinal I/R in rats.