目的 评价不同硬膜外覆盖物以及局部应用类固醇激素对腰椎术后瘢痕形成的影响，并初步探讨其机制。方法 Wistar大鼠80只随机数字表法分为4组：胶原海绵＋地塞米松组、胶原海绵组、明胶海绵组和对照组（无任何硬脊膜外覆盖物），每组实验动物20只，麻醉后在背部正中做切口行L1-L5全椎板切除，造成0.5 cm×1.0 cm骨性缺损，显露硬膜。胶原海绵＋地塞米松组动物硬膜外放置胶原海绵并注射0.1 mL地塞米松，胶原海绵组动物硬膜外放置胶原海绵，明胶海绵组动物硬膜外放置明胶海绵，对照组直接缝合肌肉组织。手术后12周重新切开伤口，观察硬膜外瘢痕形成及与硬脊膜粘连情况。应用免疫组化和Western blot检测显示硬膜外瘢痕及周围组织中TGF-β1、VEGF表达情况，比较各组间差异。结果 肉眼及光镜观察胶原海绵＋地塞米松组和胶原海绵组的硬膜外瘢痕粘连明显少于明胶海绵组和对照组，而胶原海绵＋地塞米松组与胶原海绵组之间无显著差异，明胶海绵组与对照组间无显著差异；免疫组化及Western blot检测显示胶原海绵＋地塞米松组和胶原海绵组硬膜外瘢痕及周围组织中TGF-β1、VEGF的表达显著少于明胶海绵组和对照组，而胶原海绵＋地塞米松组与胶原海绵组之间、明胶海绵组与对照组之间均无明显差异。结论 胶原海绵可以显著降低实验大鼠腰椎术后硬膜周围瘢痕增生粘连的形成，同时加用局部注射地塞米松并没有加强这种作用；局部应用明胶海绵不能减少硬膜外瘢痕增生粘连的形成。胶原海绵应用后局部的TGF-β1和VEGF的低表达可能是减少硬膜外瘢痕增生粘连的重要机制之一。

Objective To evaluate the effect of different epidural covering objects and local usage of steroid hormone on scar formation after spinal operation and to explore its mechanism. Methods Wistar rats (80) were randomly divided into four groups: collagen sponge + Dexamethasone (Dex) group, pure collagen sponge group, gelatin sponge group, and control (no epidural covering) group. After anesthesia, incisions were made in the middle of rat back, L1-L5 laminectomy was performed to leave 0.5 cm × 1.5 cm defects on the dura matter. Epidural placement of collagen sponge and Dex (0.1 mL) was given to rats in collagen sponge + Dex group, epidural placement of collagen sponge in pure collagen sponge group, epidural placement of gelatin sponge in gelatin sponge group, and just directed suture in control group. Twelve weeks after operation, we observed the epidural scar formation and the dura adhesion. Application of immunohistochemistry and Western blotting analysis showed the expression of epidural scar and surrounding tissues in TGF-β1 and VEGF, and the differences between gelatin sponge group and control group were compared. Results Through macroscopic and microscopic observation, the epidural scar adhesion of collagen sponge + Dex group and pure collagen sponge group was obviously less than that in gelatin sponge group and the control group; while no significant difference was detected between collagen sponge + Dex group and pure collagen sponge group, and between gelatin sponge group and control group. Immunohistochemistry and Western blotting analysis showed the TGF-β1 and VEGF in epidural scar and surrounding tissues in collagen sponge + Dex group and pure collagen sponge group were significantly less than those of gelatin sponge group and control group; but no significance was detected between collagen sponge + Dex group and pure collagen sponge group and between gelatin sponge group and control group. Conclusion Collagen sponge could significantly reduce the formation of postoperative epidural scar adhesion in rats, while local injection of Dex could not enhance this effect; the local use of gelatin sponge could not reduce the formation of epidural scar adhesion. The expression of TGF-β1 and VEGF in the scar and surrounding tissue is significantly lower in the rats applied with collagen sponge, which should be an important mechanism for its prevention of epidural scars.