染矽尘大鼠肺组织一氧化氮合酶的表达

目的　研究染矽尘大鼠早期炎性肺损伤过程中一氧化氮合酶 (NOS)的表达规律 ,为矽肺纤维化机制提供理论依据。方法　气管暴露法建立矽肺动物模型。测定支气管肺泡灌洗液 (BALF)中诱导型NOS(iNOS)的表达和总NOS的活力。在组织芯片上使用SP法检测大鼠肺组织iNOS的表达 ,并用Image ProPlus图像分析法对iNOS的表达进行定量测定。结果　iNOS主要表达在巨噬细胞和中性粒细胞胞浆内。与对照组相比 ,染矽尘大鼠肺组织中iNOS积分光密度于染尘后 3、7d时分别增加了1.47× 10 5 、2 .73× 10 5 ,2 8d时降低了 1.11× 10 5 ,差异均有显著性 (P <0 .0 5或P <0 .0 1)。大鼠BALF中iNOS活力在染尘后 3、7、14d时分别增加了 0 .86、1.89、0 .92U/ml ,差异均有显著性 (P <0 .0 5或P <0 .0 1)。BALF总NOS活力在染尘后 1、3、7、14d时分别增加了 1.43、2 .0 5、2 .61、2 .19U/ml,差异均有显著性 (P <0 .0 5或P <0 .0 1)。结论　在矽尘诱导下 ,大鼠肺组织中表达iNOS的细胞主要是肺泡巨噬细胞和中性粒细胞 ,其肺组织中iNOS的表达从染尘后 1d至 2 8d有一抛物线型的过程

The expression of lung nitric oxide synthase in rat exposed to silica

OBJECTIVE: To evaluate the time-effect of silica on the expression of lung tissue nitric oxide synthase (NOS) in early inflammatory damage stage of silicotic rat. METHODS: Animal models were established by direct tracheal instillation of silica into rat lungs. Total NOS and induced NOS (iNOS) activities in bronchoalveolar lavage fluid (BALF) were assayed. The expression of iNOS protein in paraffin-embedded lung sections with Streptavidin/peroxidase (SP) immunohistochemistry were measured by tissue microarray and Image-Pro Plus. RESULTS: Most of the expression of iNOS was in the cytoplasm of macrophages and neutrophils. iNOS integrated optical density (IOD) of lung tissue increased 1.47 x 10(5) and 2.73 x 10(5) more respectively in silicatreated rats 3, 7 days after exposure than in control rats (P < 0.05), and decreased 1.11 x 10(5) more 28 days after exposure (P < 0.01). The activities of iNOS in BALF increased by 0.86, 1.89 and 0.92 U/ml respectively 3, 7, 14 days after exposure (P < 0.05 or P < 0.01). The activities of total NOS in BALF increased by 1.43, 2.05, 2.61 and 2.19 U/ml respectively 1, 3, 7, 14 days after exposure (P < 0.05 or P < 0.01). CONCLUSION: After silica instillation, the iNOS-positive cells in rat lung tissue were mostly macrophages and neutrophils. There is a parabolic changing trend in the level of expression of lung iNOS during 1 - 28 day exposure to silica.