Abstract: Background　The advanced glycation end products （AGEs） accumulated on the skin type Ⅰ collagen is the carrier of long-term glycation and oxidative stress “metabolic memory”，which plays an important role in evaluating diabetes metabolic control and predicting diabetic complications.Because of intrinsic fluorescence characteristics of the AGEs，the AGE ReaderTM can noninvasively get the value of skin autofluorescence （SAF），which reflects the total content of all kinds of AGEs in human tissue.The correlation between the AGEs accumulated on skin type Ⅰ collagen and the SAF value which reflects the total amount of skin AGEs in patients with diabetic foot ulcers remains to be studied.Objective　To determine the correlation of accumulation of skin typeⅠ collagen-linked AGEs with SAF in patients with diabetic foot ulcers.Methods　This study was carried out between 11 inpatients with diabetic foot ulcers recruited from Department of Vascular Surgery，Shanghai TCM-integrated Hospital，Shanghai University of Traditional Chinese Medicine，and 8 non-diabetic inpatients with small area burns recruited from Department of Burn Surgery，Ruijin Hospital，Shanghai Jiaotong University School of Medicine between June and August，2014.Skin biopsy samples of both groups were taken from the whole skin tissue of lower-extremity wound margins or donor sites.Histomorphological characteristics of the samples were observed with light microscopy.Level of AGEs accumulated on the skin typeⅠ collagen was examined with double immunofluorescence technique.SAF measurement on the forearm was performed with the AGE ReaderTM.Results　Histomorphological observation revealed that the skin structure of non-diabetic patients was clear and complete，while the skin tissue of diabetic foot ulcer patients was atrophied and thinned，the epidermal cell layer was unclear，collagen fibers in dermis were atrophied and slender，arranged sparsely，loosely and disorderedly，and some of them were even broken and degenerated，and inflammatory cells increased significantly and distributed diffusely.The total optical density fluorescence （orange） co-expressed in skin tissue of diabetic foot ulcer group was higher than that of non-diabetic group〔（10 900±2 973） vs （6 910±1 048），t=4.06，P<0.05〕.The average SAF value of diabetic foot ulcer group was higher than that of non-diabetic group〔（2.68±0.22） AU vs （2.18±0.27） AU，t=4.47，P<0.05〕．Moreover，the extent of AGEs accumulated on skin type Ⅰ collagen was associated with the SAF value in both both diabetic foot ulcer group （r=0.65，P<0.05），and non-diabetic group （r=0.76，P<0.05）．Conclusion　Both AGEs on skin typeⅠ collagen and SAF significantly increased in patients with diabetic foot ulcers，and the two were positively correlated.So SAF may be a simply potential method to evaluate the accumulation of skin AGEs.

Key words: Diabetic foot, Foot ulcer, Advanced glycosylation end products, TypeⅠ collagen, Skin, Fluoroimmunoassay

摘要： 背景　蓄积在皮肤Ⅰ型胶原蛋白上的晚期糖化终末产物（AGEs）是长期糖化和氧化应激“代谢记忆”的载体，对判断糖尿病代谢控制及预测糖尿病并发症具有重要作用。利用皮肤AGEs内在荧光特性研发的AGE ReaderTM无创获得的皮肤自体荧光（SAF）值可反映人体组织蓄积的各种AGEs总含量。而对于糖尿病足溃疡患者皮肤Ⅰ型胶原蛋白AGEs蓄积程度与反映皮肤组织中AGEs总含量的SAF值两者之间的相关性仍有待研究。目的　探讨糖尿病足溃疡患者皮肤Ⅰ型胶原蛋白AGEs蓄积程度及其与SAF值的相关性。方法　选取2014年6—8月上海中医药大学附属上海市中西医结合医院脉管科住院治疗的糖尿病足溃疡患者11例为糖尿病足溃疡组，同期上海交通大学医学院附属瑞金医院烧伤科住院治疗的小面积烧伤的非糖尿病患者8例为非糖尿病组。标本取材于患者下肢创口边缘或供皮区的皮肤全层组织，光镜下观察两组患者皮肤组织形态学特征，免疫荧光双标法分析皮肤Ⅰ型胶原蛋白AGEs蓄积程度，采用AGE ReaderTM检测患者前臂皮肤获得SAF值。结果　光镜下观察非糖尿病组患者皮肤结构清晰完整，糖尿病足溃疡组患者皮肤组织萎缩变薄，表皮层细胞层次欠清晰，真皮层胶原纤维萎缩、纤细，排列稀疏、松散杂乱，部分胶原纤维断裂、变性，炎性细胞浸润呈弥散分布，数量明显增多。糖尿病足溃疡组患者皮肤组织免疫荧光共表达（橙黄色）光密度总和高于非糖尿病组患者〔（10 900±2 973）与（6 910±1 048），t=4.06，P<0.05〕。糖尿病足溃疡组患者SAF值高于非糖尿病组患者〔（2.68±0.22）AU与（2.18±0.27）AU，t=4.47，P<0.05〕。相关性分析显示，糖尿病足溃疡组患者皮肤Ⅰ型胶原蛋白AGEs蓄积程度与SAF呈正相关（r=0.65，P<0.05）；非糖尿病组患者皮肤Ⅰ型胶原蛋白AGEs蓄积程度与SAF呈正相关（r=0.76，P<0.05）。结论　糖尿病足溃疡患者皮肤Ⅰ型胶原蛋白AGEs蓄积明显增加，SAF值明显升高，同时皮肤Ⅰ型胶原蛋白AGEs蓄积程度与SAF值呈正相关，无创检测的SAF值或许可作为评估局部皮肤AGEs蓄积程度的简单方法。

关键词: 糖尿病足, 足溃疡, 晚期糖化终末产物, Ⅰ型胶原蛋白, 皮肤, 荧光免疫测定