de Masiero Franciéle Souza, Nassu Mariana Prado, Soares Mauro Pereira, Thyssen Patricia Jacqueline
Department of Microbiology and Parasitology, Federal University of Pelotas - UFPel, POB 354, 96010-900, Pelotas, Rio Grande do Sul, Brazil.
Parasitol Res. 2015 Aug;114(8):2865-72. doi: 10.1007/s00436-015-4487-y. Epub 2015 Apr 24.
The healing process occurs due to the interaction of cellular, molecular, and biochemical events. Regarding lesions difficult to heal, especially in immunocompromised patients, monitoring and intervention to promote healing is a constant focus of research. Another aggravating factor is the increase in the number of reported cases of microbial resistance, indicating that various dressings and drugs have been increasingly inefficient. Larval therapy (LT) involves the application of sterile fly larvae on chronic and/or infected wounds, and it is an area emerging as an alternative therapy. Before the 1940s, the LT was widely used, but fell into disuse after the appearance of antibiotics. High cost and the development of resistance by certain groups of pathogenic bacteria to these drugs encouraged the resurgence of LT, currently used in approximately 20 countries and more recently in Brazil. However, many mechanisms of action of the larvae in this system remain poorly understood. Thus, the aim of the study was to investigate histopathological findings and to evaluate possible mechanisms of action of dipteran larvae during tissue repair. Lesions were induced in 24 male Wistar rats, to evaluate the effect of the type of treatment applied. The animals were divided into four groups: larval therapy (LT), LT associated with foam dressing with silver release (LTSIL), mechanical debridement and silver foam dressing (DEBSIL), and no treatment (CONT). Skin samples were collected for histopathological analysis. In LT, inflammatory response and angiogenesis were abundant; in LTSIL, inflammatory response with neutrophil infiltration was observed; in DEBSIL, scarce inflammatory response, small numbers of macrophages and lymphocytes, and bacterial colonization in depth; and in CONT, there was bacterial colonization in deeper tissues. The observed histological events show that the larvae had an important role in promoting the inflammatory response in the wound bed, drawing the essential immune cells for tissue reconstruction, and contributing to the inhibition of bacterial growth. However, more studies on the larval-host interactions are required for increasing the application of LT in the hospital routine.
愈合过程是由于细胞、分子和生化事件的相互作用而发生的。对于难以愈合的伤口，尤其是免疫功能低下患者的伤口，促进愈合的监测和干预一直是研究的重点。另一个加重因素是微生物耐药病例报告数量的增加，这表明各种敷料和药物的效率越来越低。幼虫疗法（LT）是将无菌蝇幼虫应用于慢性和/或感染伤口，它是一种新兴的替代疗法。在20世纪40年代之前，幼虫疗法被广泛使用，但在抗生素出现后就不再使用了。某些病原菌对这些药物产生耐药性以及成本高昂，促使幼虫疗法重新兴起，目前约有20个国家使用该疗法，巴西最近也开始使用。然而，幼虫在这个系统中的许多作用机制仍知之甚少。因此，本研究的目的是调查组织病理学结果，并评估双翅目幼虫在组织修复过程中的可能作用机制。在24只雄性Wistar大鼠身上诱导损伤，以评估所应用治疗类型的效果。动物被分为四组：幼虫疗法（LT）组、与含银释放泡沫敷料联合的幼虫疗法（LTSIL）组、机械清创和银泡沫敷料（DEBSIL）组以及不治疗（CONT）组。收集皮肤样本进行组织病理学分析。在LT组中，炎症反应和血管生成丰富；在LTSIL组中，观察到有中性粒细胞浸润的炎症反应；在DEBSIL组中，炎症反应稀少，巨噬细胞和淋巴细胞数量少，且有深部细菌定植；在CONT组中，深部组织有细菌定植。观察到的组织学事件表明，幼虫在促进伤口床的炎症反应、吸引组织重建所需的关键免疫细胞以及抑制细菌生长方面发挥了重要作用。然而，需要对幼虫与宿主的相互作用进行更多研究，以增加幼虫疗法在医院常规治疗中的应用。
