观察N₂O₄吸入小鼠氮氧化物中毒模型，血清金属蛋白酶-2/9(MMP-2/9)和羟脯氨酸(HYP)的表达，并为研究其急性肺损伤机制提供实验依据。

将16只ICR小鼠，体重23～25 g，随机分为对照组和中毒组，每组8只。固定小鼠口鼻通过静态染毒装置定量吸入N₂O₄，造成肺损伤动物模型，于6 h采用眼球摘除法取血，分离血清-70^OC保存，ELISA法测定两组血清MMP-2、MMP-9和HYP含量。

对照组小鼠血清MMP-2、MMP-9、HYP含量分别为(16.75±0.84) μg/L、(35.79±4.29) μg/L、(12.46±0.80) μg/L；中毒组分别为(21.68±1.33) μg/L、(46.51±3.83) μg/L、(16.72±2.28) μg/L，两组间差异有统计学意义(P<0.05)。

N₂O₄吸入模型可导致肺水肿，监测血清MMPs-2、MMPs-9和HYP的变化对研究N₂O₄吸入中毒致肺损伤机制具有参考价值。

To determine the activation of matrix metalloproteinase (MMPS-2 and MMPs-9) in a mice model of acute lung injury by inhalation of nitrogen dioxide, in order to provide experimental data for further investigation of its mechanisms.

ICR mice, weight 23~25g, were randomly divided into two groups: control group (n=8) and poisoned group (n=8). The mouth and nose of the mice were fixed to inhalation N₂O₄ through quantitative exposure device to establish the animal model of lung injury, and then blood was collected by the eye-excised method on 6 h. The serum was separated and stored at -70℃ preservation. ELISA method was used to detect the expression of MMP-2, MMP-9 and HYP.

Serum MMP-2, MMP-9 and HYP were 16.75±0.84 μg/L, 35.79±4.29 μg/L and 12.46±0.80 μg/L in the control group, 21.68±1.33 μg/L, 46.51±3.83 μg/L and 16.72±2.28 μg/L in the poisoned group, respectively. The difference was statistically significant between the poisoned group and the control group in MMP-2, MMP-9 and HYP levels (P<0.05 ).

Exposure of nitrogen oxides leads to impairment of pulmonary edema in short time. Detection of the MMP-2, MMP-9 and HYP levels could be helpful to study the pulmonary edema.