Ⅳ型胶原蛋白和基质金属蛋白酶2在移植静脉中表达的研究

A study on collagen Ⅳ and MMP-2 expression during the period of venous intima hyperplasia (IH) in rat vein grafts

目的观察大鼠自体静脉移植后内膜增生 (IH)平滑肌细胞 (SMC)增殖、Ⅳ型胶原和基质金属蛋白酶 2 (MMP 2 )的变化。方法建立大鼠自体静脉移植模型 ,于术后不同时间处死动物。标本行HE、Verhoeff染色、SP法五溴脱氧脲嘧啶 (5′ Brdu)、Ⅳ型胶原、MMP 2免疫组化染色 ,原位杂交检测Ⅳ型胶原和MMP 2mRNA的表达。计算机图像分析仪测量移植静脉内膜 /中膜厚度、面积比 ,阳性细胞百分比 ,Ⅳ型胶原和MMP 2蛋白和mRNA阳性表达百分比。结果术后 1周移植静脉开始形成新内膜 ,2～ 4周内膜增生明显 ,8～ 12周 ,内膜增生有下降趋势。 5′ Brdu阳性细胞百分比变化趋势与内膜增生趋势相似。与正常静脉比较Ⅳ型胶原阳性区域于术后 1周明显减少 (P <0 0 5 ) ,2～ 8周管壁未见阳性区域。MMP 2在术后 1周表达明显增加 ,2周达高峰 ,8～ 12周恢复至术前水平。Ⅳ型胶原mRNA术后 3d一过性表达增多 (P <0 0 5 )。MMP 2mRNA术后 3d即迅速增高 ,1周达高峰 (P <0 0 5 )。结论静脉移植术后MMP 2高表达导致局部Ⅳ型胶原降解和破坏 ,是SMC向内膜迁移、增殖的重要原因。

Objective To investigate collagen Ⅳ and matrix metalloproteinase-2 (MMP-2)expression in intimal hyperplasia(IH) in rat vein grafts. Methods Vein graft model was constructed in rats. At day 3,week 1,2,4,8 and 12 after surgery,vein grafts were obtained and examined by HE and Verhoeff stains. The thickness and area ratio of intima/media were measured. The positive cells of 5′-Brdu were detected to indicate SMC proliferation. The positive ratio of collagen Ⅳ and MMP-2′s protein and mRNA were calculated. Results The neointima was found at 1 week post-operation. The maximal IH occurred at 2 to 4 week. The similar tendency was observed in the positive cells of 5′-Brdu. Collagen Ⅳ was on the decrease at 1 week and negative from 2 to 8 week ( P <0.05). MMP-2 expression began to rise at 1 week post-operation,and reach a peak at 2 week( P <0.05). The mRNA of collagen Ⅳ rised at 3rd day. The mRNA of MMP-2 enhanced rapidly at 3rd day and peaked at 1 week( P <0.05). Conclusion The high expression of MMP-2 leads to destroy of collagen Ⅳ that is the main cause of migration and proliferation of SMCs and IH.