MMP-9和TIMP-1在高氧致CLD新生大鼠肺组织的动态变化及其对Ⅳ型胶原的影响

目的 探讨MMP-9(基质金属蛋白酶-9)和TIMP-1(基质金属蛋白酶抑制物-1)在高氧致CLD新生大鼠肺组织中的动态变化和在Ⅳ型胶原重塑中的作用.方法 足月新生大鼠在生后12 h内分别持续吸入浓度为0.90～0.95的高氧和空气,于1,3,7,14和21 d,应用免疫组化的方法分别检测肺组织MMP-9和TIMP-1蛋白表达的动态变化,同时采用ELISA法动态检测肺组织中Ⅳ型胶原蛋白含量.结果 MMP-9在高氧3 d时的表达较空气组增强,蛋白平均灰度值为:(126.23±6.95) vs (130.38±7.36),P<0.05,其余时间点两组比较差异无显著性;TIMP-1在3 d后高氧组肺组织的表达均高于空气组,3 d和7 d时平均灰度值为:(126.22±6.49)vs(129.49±4.75),(119.70±7.33)vs(124.99±6.83)(P<0.05),14 d和21 d差异有显著性,值为(112.35±10.29)vs(120.08±7.77),(109.19±10.56)vs(118.22±6.32)(P<0.01);高氧组ColⅣ含量在14 d(24.78±5.42)vs(14.90±2.44),P<0.05]和21 d(40.27±1.94)vs(26.13±1.94),P<0.01]均高于空气组.结论 新生大鼠随着吸入高氧时间的延长,MMP-9/TIMP-1的平衡状态遭到破坏,Ⅳ型胶原降解失衡,促进了早期基膜损伤的加重和晚期伴有Ⅳ型胶原沉积的肺纤维化.

Dynamic expression and effects of MMP-9 and TIMP-1 on type Ⅳ collagen in lung tissue of neonatal rats with hyperoxia-induced CLD

Objective]To investigate the dynamic changes of matrix metalloproteinase-9 (MMP-9) and tissue inhibitors of metalloproteinase-1 (TIMP-1) in lung of neonatal rats after inhaling high concentration of oxygen (hyperoxia), and the effects on type Ⅳ collagen remodeling. Methods]Full-term newbem rats were continuously exposed to oxygen (0.90～0.95) or room air (0.2102) within 12 hours after birth. On day 1, 3, 7, 14 and 21, the contents of type Ⅳ collagen in lungs were detected by enzyme linked immunosorbent assay (ELISA), the changes of MMP-9 and TIMP-1 expression were measured by immunohistochemistry. Results]The protein content of type Ⅳ collagen in hyperoxia group increased significantly on the 14th day (24.78±5.42) vs (14.90±2.44), P<0.05]and the 21st day (40.27±1.94) vs (26.13±1.94), P<0.01]compared to that in control group, the expression of MMP-9 increased on the 3rd day in hyperoxia groups, the average values of protein were (126.23±6.95) vs (130.38±7.36) (P<0.05), while no difference was seen on other days, higher values of TIMP-1 protein expression were seen on the 3rd day (126.22±6.49) vs (129.49±4.75)]and the 7th day (119.70±7.33) vs (124.99±6.83)](P<0.05), which increased significantly compared with the control group on the 14th day (112.35±10.29) vs (120.08±7.77)]and the 21st day (109.19±10.56) vs (118.22±6.32)](P<0.01). Conclusion]With prolonged hyperoxia, the balance of MMP-9/ TIMP-1 can not been kept, type Ⅳcollagen breakdown is not balanced, which maybe make the basement membrane damage in early stage and lead to type Ⅳ collagen deposition and lung fibrosis in late stage.