Avaliação do potencial larvoterápico das espécies Hemilucilia segmentaria e Hemilucilia semidiaphana (Diptera: calliphoridae) no reparo tecidual de lesões cutâneas de ratos diabéticos

Abstract

Larval Therapy (LT), characterized by the use of disinfected fly larvae for the treatment of lesions with necrotic tissue, has emerged as a safe and effective therapeutic approach for the debridement of chronic wounds. In the search to validate new dipteran (Calliphoridae) species for LT, this study aimed to evaluate the larval therapeutic potential of the blowflies H. segmentaria and H. semidiaphana in tissue repair of cutaneous lesions in diabetic rats. This is an experimental study that sought to integrate three fronts for therapeutic feasibility: (i) understanding the immunological, debridement, and antibiofilm mechanisms of a species already validated for LT through an integrative literature review; (ii) establishing a laboratory rearing protocol for the species and disinfection of eggs for clinical application; and (iii) a randomized preclinical trial in diabetic rats, comparing LT with collagenase and saline solution.Wistar rats were induced to diabetes, followed by the induction of cutaneous lesions. After 48 hours, the experimental groups were treated with larvae of both species, the positive control group with collagenase, and the negative control group with 0.9% saline solution. To evaluate healing activity, lesions were recorded and analyzed on the 3rd, 7th, and 14th days after interventions, assessing macroscopic and histological characteristics. Wound area and contraction results were expressed as mean ± standard deviation, subjected to analysis of variance (ANOVA), and Tukey’s post-hoc test. Histological evaluation variables were analyzed using the nonparametric Mann-Whitney test, while intergroup analysis was performed with the nonparametric Kruskal-Wallis test. Values were considered significant at the 5% level, where p ≤ 0.05.The review showed that larval excretions/secretion (ES) reduce pro-inflammatory responses (neutrophils/monocytes), inhibit complement without losing antimicrobial activity, and disrupt biofilms, thereby promoting the transition to the proliferative phase. Under laboratory conditions, the developmental period from egg to adult was 10.1 days for H. semidiaphana and 12.2 days for H. segmentaria. In the process of egg sterilization for LT, the most accessible solution that achieved the highest hatching rate was 1% sodium hypochlorite. The groups treated with larvae showed superior performance in terms of debridement, early reduction of inflammatory signs, and wound contraction—being up to 15.2% greater than collagenase and 7.9% greater compared with saline solution—along with greater collagen deposition and reepithelialization. Histological evaluation revealed that LT was associated with mild inflammation, more organized collagen deposition, fibroblast and vascular proliferation consistent with orderly healing, as well as early and efficient reepithelialization. Mast cell quantification showed lower percentages in groups subjected to larval therapy, indicating significant modulation of the inflammatory response.These results confirm the potential of larval therapy with H. segmentaria and H. semidiaphana but highlight the need for further randomized preclinical trials to elucidate the specific immunological responses of each species and their causal relevance in wound repair, as well as human studies to validate the therapy regarding safety, efficacy, and cost-effectiveness, particularly in the treatment of diabetic wounds.