压疮深部组织损伤动物模型的构建及其临床意义

Development of deep tissue injury rat model and the clinical significance

目的构建大鼠深部组织损伤模型,观察和评价该模型的病理特点及临床意义。方法将25只雄性SD大鼠随机分为1个正常组和4个实验组,利用磁片循环压迫的方法,对4个实验组大鼠建立压疮深部组织损伤的动物模型,并从整体、组织和生化3个层次对压疮深部组织溃疡进行观察。结果正常组皮肤及肌肉组织肉眼及镜下观察结构完整;实验组受压组织初期出现轻度凹陷、水肿,但表面皮肤尚完整,随着时间延长,至第7天起逐渐出现少许破溃现象;进一步的病理切片观察显示皮肤、皮下、肌肉组织全层受损,各组均有大量炎症细胞浸润,复层鳞状上皮变薄,胶原纤维排列紊乱,层次欠佳,肌纤维广泛变性,横纹结构逐渐消失;镜下观察受压早期,第0天肌肉组织即已受损,且据第14天组的观察发现肌肉组织后期修复较皮肤缓慢;Tunel染色检测皮肤及肌肉组织凋亡情况,各实验组(第0、4、7、14天)与正常对照组比较,差异有统计学意义(均P<0.01)。结论利用磁片循环压迫的方法构建的压疮深部组织损伤动物模型具有组织坏死、炎症细胞聚集、细胞凋亡等特征,其病理变化符合压疮临床病理特点,且成模时间短,可控性强,是一种理想的用于研究压疮机制的动物模型。

Objective To develop a deep tissue injury （DTI）rat model, and to evaluate the pathological features and clinical signifi- cance. Methods Twenty-five male Sprague-Dawley rats were randomized into 1 control group and 4 experimental groups. Pressure was periodically applied on the gracilis muscle using a magnet in conjunction with the other on to develop the DTI rat model. Macro- scopic, histological and biochemical changes of the pressurized tissue were observed. Results Structural integrity of the skin and muscle tissue in the control group was observed by macroscopic and microscope observations. The experimental group developed mild depression and edema in the early stage, but the surface of the skin was still intact. As time goes by, ulceration developed gradually on the 7th day. Further pathological observation showed that the skin, subcutaneous and muscle tissue damaged; inflam- matory cell infiltration appeared; stratified squamous epithelium became much thinner; collagen fibers arranged in disorder; muscle fiber degeneration emerged; and transverse tubules gradually disappeared. The pressurized muscle tissue was damaged immediately after the compression under the optical microscope, and it recovered much more slowly than the skin when observed on the 14th day. Apoptosis in the skin and muscle tissue detected by TUNEL had significant differences between each experimental group and the control group （P^0.01 for all）. Conclusion A DTI rat model induced by periodical compression with magnetic steels is charac- terized by tissue necrosis, inflammatory cell infiltration and cell apoptosis. These pathological changes mimic the human pressure ulcer environment. The DTI rat model can be produced under controllable conditions in a short time, so it is an ideal animal model for pressure ulcer research.