中文摘要：

目的 探讨胰岛素样生长因子Ⅰ （IGF-Ⅰ）/细胞外信号调节激酶（ERK）通路在肺纤维化中的作用及可能机制.方法 以肺泡上皮细胞A549为研究对象.酶联免疫吸附（ELISA）法检测0、50、100 ng/ml IGF-Ⅰ对细胞培养上清液中基质金属蛋白酶（MMP）-2、MMP-9浓度的影响;用ERK特异抑制剂对IGF-Ⅰ诱导细胞MMP-2和MMP-9的表达进行阻断实验,分3组：空白对照组（未加IGF-Ⅰ刺激组）、IGF-Ⅰ刺激组、ERK抑制剂＋IGF-Ⅰ刺激组.Western印迹法检测各组细胞中ERK的磷酸化（p-ERK）情况.分别用实时荧光定量PCR法和ELISA法检测各组细胞MMP-2和MMP-9的mRNA水平和上清液中的蛋白浓度.结果 相对于0 ng/ml IGF-Ⅰ组,50、100 ng/ml IGF-Ⅰ可上调肺泡上皮细胞培养上清液中MMP-2和MMP-9的浓度[（18.30±0.11、21.80±0.09）比（13.52 ±0.19）ng/ml和（0.34±0.叭、0.39±0.01）比（0.25±0.01） ng/ml,均P＜0.001],且100 ng/ml IGF-Ⅰ组中二者浓度均高于50 ng/ml IGF-Ⅰ组（均P＜0.01）;IGF-Ⅰ刺激组中p-ERK1/2蛋白的相对表达量高于空白对照组（0.40±0.01比0.23±0.02,P＜0.05）,ERK抑制剂＋IGF-l刺激组中p-ERK1/2蛋白相对表达量低于IGF-Ⅰ刺激组（0.14±0.03比0.40±0.01,P＜0.01）;相对于IGF-Ⅰ刺激组,ERK抑制剂＋ IGF-Ⅰ刺激组抑制了MMP-2和MMP-9的mRNA水平（0.88±0.03比1.17±0.05和0.82±0.23比1.81 ±0.27,P＜0.05）和降低了细胞培养上清液中MMP-2和MMP-9的蛋白浓度[（21.70±0.32）比（29.15±0.34）ng/ml和（0.22±0.01）比（0.29±0.01） ng/ml,均P＜0.01].结论 IGF-Ⅰ可能是通过活化ERK信号通路上调肺泡上皮细胞MMP-2和MMP-9的表达,从而导致肺泡基底膜被破坏,最终促进了肺纤维化的发生.

英文摘要：

Objective To explore the role and underlying mechanisms of insulin-like growth factor Ⅰ （IGF-Ⅰ）/extracellular signal-regulated kinase （ERK） signaling pathway in lung fibrosis.Methods Alveolar epithelial cell A549 was used.The expressions of matrix metalloproteinase-2 （MMP-2） and matrix metalloproteinase-9 （MMP-9） in A549 culture media stimulated by IGF-Ⅰ were determined by enzymelinked immunosorbent assay （ELISA）.ERK inhibitor U0126 was used.And there were three groups of control,IGF-Ⅰ stimulation and RK inhibitor plus IGF-Ⅰ stimulation.The activity of ERK in three groups was measured by Western blot.The mRNA level and protein concentration of MMP-2 and MMP-9 in three groups were examined by quantitative real-time-polymerase chain reaction （qRT-PCR） and ELISA.Results The protein concentrations of MMP-2 and MMP-9 in cell culture media increased in 50,100 ng/ml IGF-Ⅰ groups as compared with 0 ng/ml IGF-Ⅰ group （（18.30 ± 0.11）,（21.80 ± 0.09） vs （13.52 ± 0.19） ng/ml and （0.34 ±0.01）,（0.39 ±0.01） vs （0.25 ±0.01） ng/ml,P 〈0.001）.And the protein concentrations of MMP-2 and MMP-9 in 100 ng/ml IGF-Ⅰ group increased versus 50 ng/ml IGF-Ⅰ group （P 〈0.01）.IGF-Ⅰ stimulation group increased the expression of p-ERK1/2 versus control group （0.40 ±0.01 vs 0.23 ± 0.02,P 〈 0.05） while ERK inhibitor plus IGF-Ⅰ stimulation group decreased the expression of p-ERK1/2 versus IGF-Ⅰ stimulation group （0.14 ±0.03 vs 0.40 ±0.01,P 〈0.01）.ERK inhibitor plus IGF-Ⅰ stimulation group inhibited the mRNA levels of MMP-2 and MMP-9 versus IGF-Ⅰ stimulation group （0.88 ± 0.03 vs 1.17±0.05 and 0.82 ± 0.23 vs 1.81 ±0.27,both P 〈0.05） and decreased the concentrations of MMP-2 and MMP-9 in culture media versus IGF-Ⅰ stimulation group （（21.70 ± 0.32） vs （29.15 ± 0.34） ng/ml and （0.22±0.01） vs （0.29 ±0.01） ng/ml,both P 〈0.01）.Conclusions IGF-Ⅰ induces the expressions of MMP-2 and MMP-9 in alveolar epithelial