Background Delayed wound healing remains a common but challenging problem in patients with acute or chronic wound following accidental scald burn injury. However, the systematic and detailed evaluation of the scald burn injury, including second-degree deep scald (SDDS) and third-degree scald (TDS), is still unclear. The present study aims to analyze the wound-healing speed, the formation of granulation tissue, and the healing quality after cutaneous damage. Methods In order to assess SDDS and TDS, the models of SDDS and TDS were established using a scald instrument in C57BL/6 mice. Furthermore, an excisional wound was administered on the dorsal surface in mice (Cut group). The wound-healing rate was first analyzed at days 0, 3, 5, 7, 15 and 27, with the Cut group as a control. Then, on the full-thickness wounds, hematoxylin and eosin (H&E) staining, Masson staining, Sirius red staining, Victoria blue staining and immunohistochemistry were performed to examine re-epithelialization, the formation of granulation tissue, vascularization, inflammatory infiltration and the healing quality at different time points in the Cut, SDDS and TDS groups. Results The presented data revealed that the wound-healing rate was higher in the Cut group, when compared with the SDDS and TDS groups. H&E staining showed that re-epithelialization, formation of granulation tissue and inflammatory infiltration were greater in the Cut group, when compared with the SDDS and TDS groups. Immunohistochemistry revealed that the number of CD31, vascular endothelial growth factor A, transforming growth factor-β and α-smooth muscle actin reached preferential peak in the Cut group, when compared with other groups. In addition, Masson staining, Sirius red staining, Victoria blue staining, Gordon-Sweets staining and stress analysis indicated that the ratio of collagen I to III, reticular fibers, failure stress, Young’s modulus and failure length in the SDDS group were similar to those in the normal group, suggesting that healing quality was better in the SDDS group, when compared with the Cut and TDS groups. Conclusion Overall, the investigators first administered a comprehensive analysis in the Cut, SDDS and TDS groups through in vivo experiments, which further proved that the obstacle of the formation of granulation tissue leads to delayed wound healing after scald burn injury in mice.

中文翻译：

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肉芽组织形成受阻导致小鼠烫伤后创面愈合延迟

背景 对于意外烫伤后的急性或慢性伤口患者来说，伤口愈合延迟仍然是一个常见但具有挑战性的问题。然而，对于烫伤烧伤，包括二度深度烫伤（SDDS）和三度烫伤（TDS）的系统和详细的评估仍不清楚。本研究旨在分析皮肤损伤后的伤口愈合速度、肉芽组织的形成以及愈合质量。方法为了评估SDDS和TDS，利用烫伤仪建立C57BL/6小鼠SDDS和TDS模型。此外，在小鼠（切割组）的背部表面进行切除伤口。首先分析第0、3、5、7、15和27天的伤口愈合率，并以Cut组作为对照。然后对全层创面进行苏木精和伊红（H&E）染色、马森染色、天狼星红染色、维多利亚蓝染色和免疫组织化学检查上皮再形成、肉芽组织形成、血管化、炎症浸润和愈合情况。 Cut、SDDS 和 TDS 组中不同时间点的质量。结果 所提供的数据显示，与 SDDS 和 TDS 组相比，Cut 组的伤口愈合率较高。H&E染色显示，与SDDS和TDS组相比，Cut组的上皮再形成、肉芽组织形成和炎症浸润更多。免疫组化显示，与其他组相比，Cut组CD31、血管内皮生长因子A、转化生长因子-β和α-平滑肌肌动蛋白的数量优先达到峰值。此外，Masson染色、天狼星红染色、维多利亚蓝染色、Gordon-Sweets染色和应力分析表明，SDDS组的I型与III型胶原比例、网状纤维、失效应力、杨氏模量和失效长度与对照组相似。正常组的愈合质量优于 Cut 组和 TDS 组。结论 总体而言，研究者首先通过体内实验对Cut组、SDDS组和TDS组进行了综合分析，进一步证明了肉芽组织形成障碍导致小鼠烫伤后创面愈合延迟。