组织型金属蛋白酶抑制剂4对血管组织胶原代谢的影响

目的探讨组织型金属蛋白酶抑制剂4(tissue inh ib itors of m atrix m etalloprote inases-4,TIMP-4)对基质金属蛋白酶(MMP)活性的作用,观察其对血管组织胶原含量的影响。方法实验动物分3组,单纯损伤组,损伤后转染AdGFP组和损伤后转染AdGFP-4组。以复制缺陷型腺病毒为载体,将TIMP-4转移到培养的大鼠血管平滑肌细胞中,用凝胶电泳酶谱分析和反向酶谱分析法检测TIMP-4对MMP活性的影响;制备大鼠颈总动脉球囊损伤模型并转染TIMP-4基因,检测TIMP-4对血管组织MMP活性及对胶原含量的影响。结果转染AdTIMP-4可使培养的血管平滑肌细胞MMP-2的活性降低至对照组(未转基因组和转染AdGFP组)的26%。动物实验中血管损伤后转染AdTIMP-4组与单纯损伤组比较,其活化形式的MMP-2几乎完全被抑制;损伤后转染AdTIMP-4组与转染AdGFP组比较,血管新生内膜的面积和细胞均减少,细胞内膜天狼星红含量的吸光度(55 030±5899)明显低于转染AdGFP组(91 530±7729,P<0.05),并不促进血管组织胶原沉积(每个细胞的胶原含量135±11 vs 118±13,P>0.05)。结论TIMP-4通过改变MMP/TIMP的平衡调节血管组织胶原代谢,在血管损伤后修复过程中发挥重要作用。

Effects of tissue inhibitor of matrix metalloproteinases-4 on the activities of matrix metalloproteinases and collagen of artery: experiment with rats

OBJECTIVE: To investigate the effects of tissue inhibitor of matrix metalloproteinases-4 (TIMP-4) on the activities of matrix metalloproteinases (MMPs) and the collagen deposition. METHODS: Vascular smooth muscle cells (VSMCs) of rat thoracic aorta were cultured and divided into 3 groups: 2 groups to be transfected with adenovirus vector containing green fluorescence protein (AdGFP) or adenovirus vector containing TIMP-4 (AdTIMP-4), and one group un-transfected. Zymography and reverse zymography were used to detect the activities of MMP-2, MMP-9 and TIMP-4 in the supernatants. Male Wistar rats underwent balloon injury of common carotid artery and then divided into 3 groups: pure injury group, AdGFP transfection group, and AdTIMP-4. transfection group. Four and 28 days later 3 and 6 rats were killed in each group respectively to undergo microscopy and examination of the activities of MMP-2, MMP-9, and TIMP-4, and collagen quantity. RESULTS: The MMP-2 activity in the VSMC culture fluid supernatant of the AdTIMP-4 group was decreased dose-dependently, however, the activity of MMP-9 did not changed significantly among the 3 groups. Bands of activated MMP-2 and MMP-9 could not be examined in the normal vessel tissues. Four hours after the injury, the activity of MMP-2 was significantly increased in the pure injury group and AdGFP group, however, was significantly decreased in the AdTIMP-4 group. Four days later no MMP activity could be detected in either group. The neoformation of tunica intima was inhibited by 66% in the AdTIMP-4 group, The collagen quantity per vessel cell was 12.1 +/- 1.0 in the AdGFP group, not significantly different from that of in the AdTIMP-4 group (11.9 +/- 1, P > 0.05), and the collagen quantity per tunica adventitia cell in the AdTIMP-4 group was 118 +/- 13, not significantly different from that of the pure injury group (135 +/- 11, P > 0.05). CONCLUSION: The regulation of MMP/TIMP balance by TIMP-4 may control the metabolism of collagen and play an important role in the vascular repair process.