The treatment of hypertrophic scar (HS) has thus far been a clinical challenge. We evaluated the therapeutic effect of CO₂ fractional laser combined with 5-fluorouracil ethosomal gel (5-FU EG) in rabbit HS model. HS model was established as standardized scars on the ventral surface of rabbit ears, divided into four groups: control (no intervention), EG treatment, laser treatment, and combined treatment group (laser plus 5-FU EG). Clinical macroscopic and H&E-stained microscopic observations were conducted to assess HS improvement. The mRNA levels of types I and III collagen, transforming growth factor-β1 (TGF-β1), and interleukin-6 (IL-6) were detected by real-time PCR. After 14 days, H&E staining shows that the thickness of HS in treatment groups was significantly lower compared with the control group, and the thickness in laser treatment group and combined treatment group was significantly lower compared with the EG treatment group. The mRNA levels of types I and III collagen, TGF-β1 were significantly low in all treatment groups, whereas IL-6 was highest in the laser treatment group at day 14. The macro- and microscopic effects of the combined and CO₂ fractional laser treatment were better compared with 5-FU EG only. Inhibition of types I and III collagen, TGF-β1 are the possible underlying mechanism of action, whereas the function of IL-6 remains to be further studied. Our study suggests that the effect of combined 5-FU EG and laser, as well as laser-only treatment are superior to 5-FU EG monotreatment. The mechanism of HS improvement is related to reduction of collagen I/III and the inhibition of TGF-β1 expression.

中文翻译：

---

CO2 点阵激光联合 5-氟尿嘧啶 Ethosomal 凝胶治疗兔动物模型肥厚性瘢痕的宏观、微观和分子作用机制

迄今为止，肥厚性瘢痕 (HS) 的治疗一直是一项临床挑战。我们评估了 CO ₂的治疗效果点阵激光联合 5-氟尿嘧啶乙醇凝胶（5-FU EG）在兔 HS 模型中的应用。以兔耳腹面标准化瘢痕建立HS模型，分为4组：对照组（不干预）、EG治疗组、激光治疗组、联合治疗组（激光加5-FU EG）。进行临床宏观和 H&E 染色的显微镜观察以评估 HS 的改善。通过实时PCR检测I型和III型胶原、转化生长因子-β1（TGF-β1）和白介素-6（IL-6）的mRNA水平。14天后H&E染色显示治疗组HS厚度较对照组显着降低，激光治疗组及联合治疗组HS厚度较EG治疗组显着降低。₂点阵激光治疗优于仅 5-FU EG。抑制 I 型和 III 型胶原蛋白、TGF-β1 是可能的潜在作用机制，而 IL-6 的功能仍有待进一步研究。我们的研究表明，5-FU EG 联合激光以及仅激光治疗的效果优于 5-FU EG 单一治疗。HS改善的机制与I/III胶原蛋白的减少和TGF-β1表达的抑制有关。