咪喹莫特抑制兔耳瘢痕增生的机制研究

Imiquimod Inhibit Scar Formation in Rabbit Ear Hypertrophic Scar Model

目的:研究咪喹莫特抑制兔耳瘢痕增生的作用及可能机制。方法:选取10只新西兰大耳白兔,雌雄不限,根据本实验室的改良方法建立兔耳瘢痕模型,每只兔耳腹侧做六个直径为1cm的圆形创面,每个相距1.5cm,双侧对称,左耳为实验组涂抹5%咪喹莫特软,右耳为对照组涂抹等量凡士林软膏,待术后14天上皮化均完全后开始涂抹,一日一次。分别于术后14天、21天、28天、35天及42天同一时间点空气栓塞随机处死2只兔子,后沿每个瘢痕边缘外周的0.5cm处环形切下,经瘢痕最凸点直径一切为二,一半固定后行苏木精-伊红(HE)染色及Masson三色法染色,观察形态学差异,测量并计算瘢痕增生指数(Scar elevation index,SEI);另一半用于提取RNA,反转录后行Real-time PCR检测细胞外基质Ⅰ型胶原(Collagen-Ⅰ,Col-Ⅰ),细胞因子IFN-γ及IL-4的表达。结果:HE及Masson染色可见实验组胶原沉积较对照组明显减少,SEI显示空白对照组于术后第21天增生程度达到高峰,其增生程度明显高于实验组;Real-time PCR结果可见实验组Col-Ⅰ及IL-4的表达在各时间点明显降低,且IFN-γ的表达较对照组增高。结论:咪喹莫特可能通过调节IFN-γ及IL-4的表达来发挥抑制瘢痕增生的作用。

Objective： To investigate the inhibitory effect and mechanism of imiquimod on rabbit ear hypertrophic scar formation. Methods： Ten New Zealand White rabbits were employed in this study. Rabbit ear hypertrophic scar model was builded on the basis of the previous literature of our laboratory. Six round wounds were cut in each rabbit ears ventral that diameter of lcm, bilateral symmetry. All the left ear wounds were treated with 5% imiquimod cream. The control group contains all the fight ear wounds and were treated with vaseline ointment at the same time. Every wounds were applied cream after healing, once a day. Both of the groups were harvested at the same time on the 14th, 21st, 28th, 35th and 42nd day after operation. Two rabbits were killed by air embolism every time. The speci- mens were cut along the edge outside the scar at 0.5cm ring, then cut through the most thickest point in half. Hematoxylin-eosin staining and Masson trichrome staining were performed after fixing to observe morphological differences. The expression of Col- I, IFN-γ and IL-4 was detected by Real-time PCR. Results： The sections of HE and Masson show that compared with that in the blank control group, the level of the collagen deposition reduced significantly in the treated group. （P〈0 05）. The expression of Col- I, and IL-4 were distinctly down-regulated in the treatment group. The expression of IFN-γincreased compared with that in the control group. Conclusion： Im- iquimod may inhibit scar formation by regulating the expression of IFN-γ and IL-4.