Falanga Vincent, Schrayer David, Cha Jisun, Butmarc Janet, Carson Polly, Roberts Anita B, Kim Seong-Jin
Department of Dermatology, Roger Williams Medical Center, Elmhurst Building, 50 Maude Street, Providence, RI 02908, USA.
Wound Repair Regen. 2004 May-Jun;12(3):320-6. doi: 10.1111/j.1067-1927.2004.012316.x.
Experimentally induced wounds in animal models are useful in gaining a better understanding of the cellular and molecular processes of wound healing, and in the initial evaluation of the safety and effectiveness of potential therapeutic agents. However, studying delayed healing has proved difficult in animals, whose wounds heal within a few days. In this report, we describe a novel method for establishing mouse wounds that require up to 3 weeks or more for complete closure, and we show the validity of this model in Smad3 null mice, which are known to display accelerated healing. Full-thickness wounds, measuring 0.3 by 1.0 cm, were made down to fascia on the dorsal aspect of the mouse tail in Smad3 knock-out mice and control littermates, approximately 1 cm distal to the body of the animal. The wounds were left to heal by secondary intention and were assessed histologically by computerized planimetry for wound closure at various times after wounding. The wounds in wild-type mice displayed delayed healing, with full closure occurring between 14 and 25 days after wounding. Complete closure of similar wounds in Smad3 null mice healed 30 percent faster (p < 0.01). By immunostaining for ki67, a marker for proliferation, Smad3 null animals also showed increased proliferation of dermal wound cells by day 4 after wounding. Cultured dermal fibroblasts from Smad3 null mice had increased baseline DNA synthesis and, interestingly, an enhanced response to transforming growth factor-beta1. By Western blot analysis, Smad3 null mice fibroblasts showed a compensatory increase in mitogen-activated protein kinase phosphorylation in response to transforming growth factor-beta1, suggesting that mitogen-activated protein kinase overcompensation together with loss of Smad3 may be involved in the modulation of faster healing. We conclude that this novel tail-wounding model may be useful for studying delayed wound closure.
在动物模型中通过实验诱导的伤口，有助于更好地了解伤口愈合的细胞和分子过程，以及对潜在治疗药物的安全性和有效性进行初步评估。然而，在动物身上研究延迟愈合已被证明具有难度，因为动物的伤口在几天内就会愈合。在本报告中，我们描述了一种建立小鼠伤口的新方法，这种伤口需要长达3周或更长时间才能完全愈合，并且我们展示了该模型在已知表现出加速愈合的Smad3基因敲除小鼠中的有效性。在Smad3基因敲除小鼠及其对照同窝小鼠的小鼠尾巴背侧，距动物身体约1厘米处，制作深度达筋膜的0.3×1.0厘米全层伤口。让伤口通过二期愈合自行愈合，并在受伤后的不同时间通过计算机图像分析进行组织学评估伤口闭合情况。野生型小鼠的伤口显示出延迟愈合，在受伤后14至25天之间完全闭合。Smad3基因敲除小鼠中类似伤口的完全闭合速度快30%（p<0.01）。通过对增殖标志物ki67进行免疫染色，Smad3基因敲除动物在受伤后第4天也显示出真皮伤口细胞增殖增加。来自Smad3基因敲除小鼠的培养真皮成纤维细胞的基线DNA合成增加，有趣的是，对转化生长因子-β1的反应增强。通过蛋白质免疫印迹分析，Smad3基因敲除小鼠成纤维细胞在对转化生长因子-β1的反应中，丝裂原活化蛋白激酶磷酸化出现代偿性增加，这表明丝裂原活化蛋白激酶的过度代偿以及Smad3的缺失可能参与了更快愈合的调节。我们得出结论，这种新的尾部创伤模型可能有助于研究延迟伤口闭合。
