The influence of Lucilia sericata larval secretions on fibroblast lineage: an in vitro cell culture study

Lucilia sericata larval secretion (LS) has been associated with wound-related biological processes; however, its effects on fibroblast responses under oxidative stress conditions remain insufficiently characterized. This study aimed to evaluate the dose-dependent effects of LS on 3T3 fibroblast behavior in an H₂O₂-induced oxidative stress model. 3T3 mouse fibroblasts were exposed to H₂O₂ and/or different doses of LS, and cellular responses were evaluated at 0, 24, and 48 h. Cell migration was assessed using an in vitro scratch assay, proliferative activity was evaluated by Ki-67 immunofluorescence staining, and cell viability was examined using trypan blue exclusion staining. Collagen type I alpha 1 chain (Col1a1) expression was assessed by immunofluorescence and ELISA, while total antioxidant levels (TAL) and total oxidant levels (TOL) were measured to evaluate oxidative balance. Ultrastructural changes were examined by transmission electron microscopy. H₂O₂ exposure reduced fibroblast proliferation and migration and was associated with oxidative imbalance and marked morphological alterations. LS treatment, particularly at lower doses, improved fibroblast proliferation and migration under oxidative stress conditions and was associated with increased Col1a1 levels and improved TAL/TOL balance. Ultrastructural evaluation further showed that LS-treated fibroblasts displayed better preservation of cellular and mitochondrial morphology compared with H₂O₂-treated cells. In contrast, higher LS doses were associated with reduced monolayer integrity, altered adhesion, and spheroid-like cellular aggregation, indicating a dose-dependent cellular response. These findings suggest that LSmay modulate fibroblast-associated cellular responses under oxidative stress in a dose-dependent manner, with favorable effects at lower doses and morphological disruption at higher doses. Further mechanistic and tissue-level studies are required to clarify the pathways and translational relevance of these cellular effects.