小鼠放射性肺损伤中细胞间黏附因子-1的表达

目的利用小鼠放射性肺损伤模型，了解细胞间黏附因子-1（ICAM-1）在放射性肺损伤不同阶段中的表达及其意义。方法成年雌性C57BL／6小鼠90只，按随机表分作2组：①对照组（36只）：不做任何处理；②照射组（54只）：全肺单次照射12Gy。于照射后1、24和72h及1、2、4、8、16和24周取照射组及相同鼠龄对照组小鼠肺组织，分别用HE和Masson染色在光镜下观察组织病理改变和胶原纤维沉积；免疫组织化学S-P法观察ICAM-1蛋白和白细胞共同抗原（CD45）蛋白表达，用碱水解法测定羟脯氨酸含量和实时定量RT—PCR法检测ICAM-1 mRNA相对含量。结果光镜下，照射组小鼠肺组织较对照组组织学改变和胶原纤维沉积明显，免疫组织化学结果显示，对照组小鼠肺组织中ICAM-1和炎性反应细胞的阳性细胞数均相对较低，照射组的阳性细胞数较之明显增高（P〈0．01）；羟脯氨酸含量的测定结果显示，照射组小鼠肺组织中的羟脯氨酸含量较对照组明显增高（P〈0．05）；实时定量RT-PCR的结果显示，照射组的ICAM-1 mRNA的表达水平较对照组均明显升高（P〈0．01）。结论在放射性肺损伤的过程中，ICAM-1是一重要的细胞因子，不仅介导早期炎性反应细胞的黏附和浸润，还参与后期放射性肺纤维化的形成。

Expression of ICAM-1 in mice with radiation induced lung injury

Objective To observe the expression of intercellular adhesion molecule-1(ICAM-1) in mice with radiation induced lung injury and to study the function of ICAM-1.Methods The thoraces of C57BL/6 mice were exposed to either sham irradiation or single fraction of 12 Gy. Two groups were defined as received sham-irradiation (C group) and underwent irradiation (X group). Mice were sacrificed at hours 1, 24, 72 and weeks 1, 2, 4, 8, 16, 24 after irradiation. The lung tissues were removed and processed for definitive analysis, including HE and Masson staining, the hydroxyproline content, the immunohistochemistry and the real-time quantitative RT-PCR.Results Compared with C group, there was a significant histological and pathologic change in X group. And there was a significantly elevated level of positive cell counts of ICAM-1 and inflammatory cells in X group (P<0.01). Similarly, there was a significantly elevated level of hydroxyproline in X group(P<0.05). Moreover, the results of real-time quantitative RT-PCR showed that the relative mRNA expression of cytokine ICAM-1 in X group was significantly higher than that of C group(P<0.01). ConclusionsAs an important cytokine in radiation-induced lung injury, ICAM-1 can not only mediate the inflammation cells adherence and infiltration, but also be involved in radiation induced lung fibrosis.