Impact of Echinococcus granulosus Cyst Fluid on the Phenotypic Dynamics and Degranulation of RBL-2H3 Mast Cells

This study aimed to evaluate the effects of Echinococcus granulosus cyst fluid (EgCF) on the phenotypic characteristics and degranulation activity of mast cells during echinococcosis-associated hypersensitivity reactions, using the RBL-2H3 rat basophilic leukemia cell line as an in vitro model.

The cytotoxic effects of EgCF on RBL-2H3 cells were assessed using the Cell Counting Kit-8 assay. Degranulation activity was quantified by measuring β-hexosaminidase release. Morphological alterations and cytoskeletal changes were evaluated via toluidine blue staining and phalloidin-labeled confocal laser scanning microscopy. Apoptotic cell populations were quantified using flow cytometry.

EgCF at mass concentrations ranging from 0.5 to 5 mg/mL significantly enhanced cell proliferation. Higher EgCF concentrations were associated with increased morphological deformation, as evidenced by toluidine blue staining, and with significantly elevated β-hexosaminidase release compared to the control group (p < 0.01). Flow cytometry revealed a statistically significant increase in apoptosis rates in the treated groups (p < 0.01). Within 30 minutes of EgCF exposure, phalloidin staining showed notable cytoskeletal reorganization, including cellular wrinkling and pseudopodia extension. These morphological changes were partially reversed within 45 to 60 minutes.

EgCF induces morphological transformation and promotes degranulation in mast cells, with the intensity of these responses correlating positively with EgCF concentration. These findings suggest a dose-dependent role of EgCF in modulating mast cell activity during parasitic hypersensitivity responses.