大鼠皮肤切创愈合过程中caspase-3、Toll样受体4的表达与时间相关性的研究

目的研究大鼠皮肤切创愈合过程中caspase-3、Toll样受体4（TLR4）的表达与损伤时间的关系,为损伤时间的推断提供实验依据。方法采用随机数字表法将健康大鼠63只随机分为正常对照组（3只）、生前造创组（33只）、死后造创组（12只）和死后稳定性组（15只）。建立大鼠背部皮肤切创模型,运用苏木精-伊红染色技术、免疫组织化学染色技术观察各组caspase-3和TLR4的表达情况;使用Image-Pro Plus图像分析软件、SPSS统计分析软件对实验结果进行处理。结果 caspase-3和TLR4主要在炎性细胞内表达,在正常皮肤组织的表皮层、毛囊及皮脂腺细胞内也均有表达。生前造创组：除0 h组外,其余各组与对照组比较差异均有统计学意义（P〈0.05）;伤后0.5 h,在创缘毛囊周围中性粒细胞中可见少量caspase-3及TLR4表达;随着炎细胞浸润,caspase-3及TLR4阳性细胞率增加,3 d时达峰值;而后逐渐降低,主要表达于成纤维细胞及单核-巨噬细胞;10 d时,炎细胞大量减少,阳性表达主要在成纤维细胞。死后造创组：细胞表达结果与对照组差异无统计学意义。死后稳定性组：caspase-3、TLR4阳性细胞率与死后即刻比较差异无统计学意义（P〉0.05）。结论在皮肤创伤愈合过程中caspase-3、TLR4阳性细胞率具有一定的规律性及时间相关性,且两者在25℃温度环境中具有较好的稳定性,可望成为法医学损伤时间推断的指标。

A Study on the Relationship between the Expression of Caspase-3 and Toll-like Receptor 4 and the Injury Time in Incised Rat Skin Healing

Objective To investigate the expression of caspase-3 and Toll-like receptor 4（TLR4） in the incised rat skin healing process and its relationship with the wound time and to provide an experimental evidence for the prediction of injury time. Methods After the rat incised wound model was established, hematoxylin-eosin dyeing technology and immunohistochemical staining technique were used to observe the expression of caspase-3 and TLR4. Then Image Pro Plus Image analysis software and SPSS statistical analysis software were used to deal with the experimental results. Results Caspase-3- and TLR4-positive cells were detected in epidermis, hair follicle and sebaceous gland cells in the control skin. The expression of caspase-3 and TLR4 of the ante mortem groups were signifi cantly different compared with the control group except the 0 h group（P 〈0.05）. Caspase-3-and TLR4-positive cells were detected in neutrophils around the hair follicle half an hour later. Caspase-3- and TLR4-positive cell rate increased with the infi ltration of infl ammatory cells. Caspase-3- and TLR4-positive cell rate reached the maximum on the 3 rd day, and then it began to decrease, and they were mainly expressed in fi broblasts and mononuclear macrophages. Caspase-3-and TLR4-positive cells were mainly expressed in fi broblasts on the 10 th day. There was no signifi cant differences between the postmortem injury groups and the normal control groups（P 〉0.05）. Conclusion Caspase-3- and TLR4-positive cell rate is time dependent and stable in 25℃ temperature environment which makes it possible to determine the time of injury.