转化生长因子-β_1抗体对肺损伤纤维化大鼠细胞外基质重建紊乱的调控

Regulatory effect of TGF-beta 1 antibodies on extracellular matrix reconstruction in rats with lung injury fibrosis

目的转化生长因子β(transforming growth factor-β,TGF-β)能调节金属基质蛋白酶(matrix metalloproteinase,MMPs)和金属基质蛋白酶抑制剂(matrix metalloproteinase inhibitors,TIMPs)表达,从而影响肺损伤后细胞外基质(extracellular matrix,ECM)重建。迄今为止,有关内毒素所致肺损伤过程中TGF-β1与MMPs/TIMPs比例调控、ECM重建紊乱的确切作用机制目前尚不清楚。文中探讨TGF-β1抗体对内毒素致急性肺损伤大鼠中MMP、TIMP的表达及肺损伤纤维化的影响。方法 SD大鼠56只分为对照组(n=16)、内毒素组(n=20)及内毒素+TGF-β1抗体组(抗体组,n=20),内毒素组和抗体组气管内联合腹腔内注射内毒素诱导肺损伤纤维化,其中抗体组在灌注内毒素前先予尾静脉注射TGF-β1抗体,对照组在气管内及腹腔内注射等量的等渗盐水。分别于造模后第1、5、9、14天处死大鼠,取血及肺组织标本,检测肺组织湿/干重比(W/D)、弥漫性肺泡损伤(diffuse alverolar damage,DAD)评分、羟脯氨酸(hydroxyproline,Hpy)活性和TGF-β1、MMP-2及TIMP-1的表达情况。结果与对照组相比,内毒素组大鼠肺组织DAD评分、Hpy活性、TGF-β1、MMP-2及TIMP-1表达均较高,差异具有统计学意义(P<0.05);抗体组大鼠DAD评分、Hpy、MMP-2及TIMP-1较对照组高,差异有统计学意义(P<0.05)。与内毒素组相比,经TGF-β1抗体干预后的抗体组大鼠Hpy、TGF-β1及TIMP-1有所下降,差异有统计学意义(P<0.05)。3组的MMP-2表达在造模后第1、5、9天逐渐增高,第9天达到最高值,而后下降;Hpy活性、TGF-β1及TIMP-1表达则在造模后持续升高。结论 TGF-β1分子介导的MMP/TIMPs失衡、ECM重建紊乱可能是内毒素性肺损伤纤维化发生的重要原因;TGF-β1抗体能一定程度上减轻肺损伤纤维化程度,具有保护作用。

Objective Transforming growth factor-β（ TGF-β） can regulate the expressions of matrix metalloproteinase （MMP） and matrix metalloproteinase （TIMP） inhibitors, thus affecting the reconstruction of extracellular matrix （ECM） after lung in-jury.So far, little is known about the regulation of TGF-β1 and MMPs/TIMPs ratio in endotoxin-induced lung injury as well as about the exact mechanisms of ECM reconstruction disorders .This study was to investigate the effects of TGF-β1 antibodies on the expressions of MMP and TIMP inhibitors and lung injury fibrosis in rats with endotoxin-induced acute lung injury . Methods Fifty-six male SD rats were randomly divided into three groups, normal （n=16）, LPS （n=20）, and LPS＋TGF-β1（L＋T, n=20）.The rats of the LPS and L＋T groups received intraperitoneal and intra-tracheal injection of endotoxin to induce lung injury fibrosis , the latter intrave-nously injected with TGF-β1 antibodies previously .The normal rats received intra-tracheal and intra-abdominal injection of the same a-mount of saline.At 1, 5, 9 and 14 days after modeling, all the rats were killed and blood and lung tissue samples obtained to detect the wet/dry lung tissue （ W/D ） ratio, diffuse alveolar damage （ DAD） score, hydroxyproline activity （ Hpy） , and the expressions of TGF-β1 , MMP-2 and TIMP-1. Results The DAD score, Hpy ac-tivity, and expressions of TGF-β1 , MMP-2 and TIMP-1 were signifi-cantly higher in the LPS group than in the normal control （ P ＆lt; 〈br〉 0.05）, and so were the DAD score, Hpy activity, MMP-2, and TIMP-1 in the L＋T group than in the controls （P＆lt;0.05）.Com-pared with the LPS group, Hpy, TGF-β1 and TIMP-1 were markedly decreased in the L ＋T group （P＆lt;0.05）.The expression of MMP-2 was gradually increased at 1, 5 and 9 days after modeling , reaching the peak at 9 days and then beginning to decline .The Hpy activity, TGF-β1 and TIMP-1 expressions kept rising after modeling . Conclusion The MMP/TIMP imbalance and ECM reconstruc-tion disorders mediated by the TGF-β1 signaling pathway may be an important cause of fibrosis in endotoxin-induced lung injury . TGF-β1 antibodies can exert a protective effect by alleviating lung injury fibrosis .