Sayani K, Dodd C M, Nedelec B, Shen Y J, Ghahary A, Tredget E E, Scott P G
Division of Plastic Surgery, Department of Surgery, University of Alberta, Edmonton, Alberta, Canada.
Histopathology. 2000 Mar;36(3):262-72. doi: 10.1046/j.1365-2559.2000.00824.x.
We have previously shown that hypertrophic scar tissue from burn patients contains abnormally high amounts of the proteoglycans versican and biglycan and reduced amounts of decorin, in comparison with normal dermis or mature scar. The lack of decorin may account for the poor organization of collagen fibrils in the nodular areas of these scars. Decorin has also been reported to neutralize the fibrogenic growth factor TGF-beta1. This study was conducted to monitor the time-course of expression of decorin in healing burn wounds by in-situ hybridization to determine whether its absence from hypertrophic scars could result from reduced synthesis.
Scar tissue from 19 patients and normal dermis from six patients, was fixed in paraformaldehyde, embedded in paraffin and sectioned. Digoxigenin-labelled cRNA probes were prepared from a plasmid containing a 622-bp insert of human decorin cDNA and used for in-situ hybridization. Total numbers of connective tissue cells and cells positive for decorin mRNA were counted in 10 random fields in the upper (papillary), middle and lower (reticular) one-thirds of the dermis. In all regions the number and percentages of cells with decorin mRNA were low during the first 12 months after injury (eight samples), much higher between 12 and 36 months (seven samples) and low and similar to those in normal skin after 36 months (five samples). The differences between intermediate and early or late stage samples were statistically significant (one-way ANOVA). Immunohistochemistry showed little staining for decorin in early stage samples and much stronger staining in mid-stage. Late stage tissue showed intense staining for decorin, almost comparable to that in normal dermis.
Expression of decorin in burn wounds is suppressed for about 12 months and then increases at a time when resolution of hypertrophic scarring is generally considered to occur.
我们之前已经表明，与正常真皮或成熟瘢痕相比，烧伤患者的肥厚性瘢痕组织中蛋白聚糖多功能蛋白聚糖和双糖链蛋白聚糖含量异常高，而核心蛋白聚糖含量减少。核心蛋白聚糖的缺乏可能是这些瘢痕结节区域胶原纤维排列紊乱的原因。据报道，核心蛋白聚糖还能中和促纤维化生长因子转化生长因子β1。本研究通过原位杂交监测愈合烧伤创面中核心蛋白聚糖的表达时间进程，以确定其在肥厚性瘢痕中缺失是否可能是由于合成减少所致。
取自19例患者的瘢痕组织和6例患者的正常真皮，用多聚甲醛固定，石蜡包埋并切片。从含有622bp人核心蛋白聚糖cDNA插入片段的质粒制备地高辛标记的cRNA探针，并用于原位杂交。在真皮上部（乳头层）、中部和下部（网状层）的三分之一区域随机选取10个视野，计数结缔组织细胞总数和核心蛋白聚糖mRNA阳性细胞数。在损伤后的前12个月（8个样本），所有区域中具有核心蛋白聚糖mRNA的细胞数量和百分比都很低，在12至36个月之间（7个样本）要高得多，而在36个月后（5个样本）则很低且与正常皮肤相似。中期与早期或晚期样本之间的差异具有统计学意义（单因素方差分析）。免疫组织化学显示早期样本中核心蛋白聚糖染色较少，中期染色较强。晚期组织显示核心蛋白聚糖染色强烈，几乎与正常真皮相当。
烧伤创面中核心蛋白聚糖的表达在约12个月内受到抑制，然后在通常认为肥厚性瘢痕消退的时候增加。
