转染人血红素加氧酶-1基因对大鼠血管平滑肌细胞抗氧化损伤的作用

Increased resistance against oxidant-induced injury in the rat vascular smooth muscle cells transfected with human heme oxygenase 1 gene

本实验构建含人血红素加氧酶 1(hHO 1)基因的逆转录病毒载体XM 6/hHO 1,将其导入离体培养的大鼠血管平滑肌细胞 (vascularsmoothmusclecells,VSMC) ,观察外源性hHO 1基因在VSMC内的表达及其抗活性氧损伤作用。结果表明 :( 1)hHO 1基因可在靶细胞中明显表达 ,转染VSMC的HO 1蛋白表达和HO酶活性分别比非转染细胞高 1 8倍和 2 0倍 ;( 2 )转染hHO 1的VSMC可对抗大剂量H2 O2 对细胞的损伤作用 ,表现为细胞存活率增加和乳酸脱氢酶 (LDH)漏出减少 ,上述保护作用可被HO特异性抑制剂锌原卟啉IX (Zinc protoporphyrinIX ,ZnPP IX)所阻断。研究结果提示 ,外源性HO

The heme oxygenase 1 (HO 1), a rate limiting enzyme in heme metabolism, has been recently defined as a novel stress stimulated protein, since the intracellular expression of HO 1 in response to various stimuli as oxidation, ischemia and endotoxin injury has been proved to be able to protect the cells from damage. In this study, a retroviral vector containing human HO 1 gene was constructed and transfected to rat vascular smooth muscle cells (VSMCs). Using Southern and Northern blot analyses, the integration and mRNA expression of HO 1 gene in the transfected cells were confirmed. The profound protein expression of HO 1 as well as HO enzyme activity in the transfected cells increased by 1 8 fold and 2 0 fold respectively as compared with the non transfected cells. It was found that the HO 1 transfected VSMCs presented dominant resistance to toxicity produced by exposure to H 2O 2, as a significant protective effect of HO 1 marked by cell survival and LDH leakage was observed when 200, 400 and 600 μmol/L of H 2O 2 were used. The protection of HO 1 rapidly declined after the transfected VSMCs were pretreated 24 h with an HO 1 specific inhibitor (ZnPP IX). The results of this investigation suggest that the functional expression of HO 1 gene within VSMCs raises an alternative ability to protect the vascular cells against active oxygen injury.