表皮干细胞在糖尿病创面愈合过程中的动态变化

DYNAMIC CHANGE OF EPIDERMAL STEM CELLS IN THE WOUND HEALING COURSE OF DIABETIC RATS

目的 观察糖尿病（diabetes mellitus，DM）大鼠创伤后不同时期表皮厚度、表皮干细胞（epidermalste mcells，ESCs）数量变化和分布特征及创面愈合率等动态变化，探讨ESCs与DM皮肤创面难愈之间的关系。方法 48只Wistar大鼠，雄性，体重180～200g。随机分为DM组和正常对照组，各24只。DM组大鼠制备DM大鼠慢性创面愈合模型。两组大鼠同时用特制打孔器在大鼠背部脊柱两侧约1．5cm制作直径1．8cm、面积2．54cm。的全层皮肤缺损（共计96个创面），分别在致伤后第3、7、14和21天拍摄创面，计算创面愈合率；取创缘及肉芽组织，行HE染色及角蛋白19（keratin19，K19）和β1整合素抗体免疫组织化学染色，显微图像分析系统测量表皮厚度、阳性部分面积及灰度值。结果 致伤后第3、7、14和21天，正常对照组大鼠创面愈合率分别为24．48％±3．37％、50．46％±1．26％、92．82％±2．12％和99．41％±0．66％，而DM组分别为2．43％±1．02％、40．59％±1．65％、80．77％±3．57％和85．40％±0．94％，两组同时期比较差异有统计学意义（P〈0．01）。致伤后第3、7、14和21天，正常对照组表皮厚度分别为26．43±3．21、33．29±3．52、31．53±3．35和26．01±3．19p．m，DM组表皮厚度分别为23．58±2．33、31．02±3．38、33．72±5．49和21．80±4．02p．m，致伤后第3、21天，二者比较差异有统计学意义（P〈0．01）。致伤后第3、7、14和21天，正常对照组K19染色的平均阳性单位（positiveunit，PU）值分别为91．68％、93．14％、72．27％和70．31％，而DM组分别为40．29％、40．79％、29．94％和10．37％；正常对照组β1整合素染色的平均PU值分别为49．60％、91．16％、77．13％和57．17％，DM组分别为38．94％、24．16％、61．36％和38．83％，与正常对照组同时期比较，DM组K19和β1整合素染色的平均PU值都降低，且差异有统计学意义（P〈0．05）。结论 ESCs数量少和活性低可能是DM创面难愈的重要机制之一。

Objective To observe the epidermal width, the amount variation and distribution character of epidermal stem cells（ESCs） and the wound healing rate at different periods of diabetes mellitus （DM） rats after trauma, then to study the correlation of them. Methods Forty-eight Wistar rats were divided into DM group and normal control group randomly（n= 24）. The DM rats were induced by streptozocin （STZ） and then made chronic healing wound by special perforex. At the 3rd, 4th, 7th,14th and 21st days after trauma, the healing rate was calculated, the wound edge and granulation tissue were obtained for haematoxylin-eosin （HE） staining and immunohistochemical staining of keratin 19（K19） and 131 integrin. Then the epidermal width, the area and the gradation value of positive unit （PU） were measured. Results At the 3rd, 7th, 14th and 21st days after trauma, the wound healing rates of normal rats were 24.48%± 3.37%, 50.46%±1.26%, 92.82%± 2.12%0 and 99.41%±0.66%0 respectively, while those of DM rats were 2.43±1.02% 40.59%±1.65%, 80.77%±3.57% and 85.40%±0.94% respectively, showing significant differences （P〈0.01）. Before trauma, there was no significant difference in the epidermal width between normal rats and DM rats （P〉0.05）： However, at the 3rd, 7th, 14th and 21st days after trauma, the epidermal widths of normal rats were 26.43 ±3.21, 33.29 ± 3.52, 31.53± 3.35 and 26.01 ± 3.19 μm respectively, while those of DM rats were 23.58 ± 2.33, 31.02 ± 3.38, 33.72± 5.49 and 21.80 ± 4.02μm respectively, the epidermal widths in DM rats were significantly lower than those in normal rats （P〈0. 01）. The average PU value of K19 in normal rats were 91.68%, 93.14%, 72.27% and 70.31% respectively, while those in DM rats were 40.29%, 40.79%, 29.94% and 10.37% respectively. The average PU value of 131 integrin in normal rats were 49.6%, 91.16%, 77.13% and 57.17% respectively, while those in DM rats were 38.94%, 24.16%, 61.36% and 38.83%. The results indicated that the average PU values of K19 and β1 integrin in DM rats were significantly lower than those in normal rats（P〈0. 05）. Conclusion The amount and activity decrease of ESCs may be one of the important mechanisms of difficult recovering wounds of DM rats.