Immunohistochemical characterization of pancreatic delta cell as potential target for dibutyl phthalate toxicity in Wistar rats

Purpose: To investigate the endocrine disrupting potential of dibutyl phthalate (DBP) on δ-cells of the pancreas. Methods: A total of 40 adult Wistar rats comprised of 20 males and 20 females were each grouped into control and study groups. Control groups had spontaneous access to food and water (controlspontaneous), and oral gavage normal saline (3.2 mL/kg; control-forced) every day for 8 weeks. Study group were exposed to DBP in their drinking water (0.8 µg/L; study-spontaneous), and oral gavage 0.8 µg DBP/kg for 8 weeks (study-forced). Blood glucose level was monitored weekly, and oral glucose tolerance test (OGTT) was conducted at the end of the experiment. The animals were sacrificed, pancreas excised, re-sectioned and processed for hematoxylin and eosin (H&E) staining, and immunohistochemical assay for identification of somatostatin (SST) protein. Results: The H & E-stained pancreatic sections revealed a typical structural pattern of the endocrine and exocrine pancreas. The immunohistochemical assay using an anti-SST antibody indicated δ-cell immunoreactivity, mainly localized at the periphery of the islet population. The cell body of δ-cells exhibited characteristic neuron-like shaped filopodia-like extensions. The DBP-exposed animals demonstrated significant SST immunoreactivity compared to control (p < 0.05). The forced mode of DBP exposure showed a more significant effect on SST absorbance with no sex differences compared to drinking water exposure (p < 0.05). Conclusion: This study shows that DBP toxicity induces alteration in the pancreatic δ-cells' SST immunoreactivity, which depends on exposure irrespective of sex.