Zinc Oxide Nanoparticles' Acute and Subacute Oral Toxic Effects on Pancreas in Adult Male Albino Rats

Abstract

Zinc oxide nanoparticles (ZnO-NPs) are being progressively employed in various industries, including cosmetics, textiles, and sun protection products. Due to their widespread application, concerns have emerged about their potential health hazards, especially through environmental exposure. This study was conducted to assess the acute and subacute toxicological impact of orally administered ZnO-NPs (30 ± 5 nm) on the pancreas of adult male albino rats. In this study, the size of ZnO-NPs was determined by using transmission electron microscopy (TEM) as provided by the company. Eighty male albino rats (2.5-3 months old) were allocated into two equal groups to evaluate acute (1 day) and subacute (28 days) ZnO-NP toxicity (40 rats each). Each was further divided into control (negative and positive), low-dose (175 mg/kg), and high-dose (350 mg/kg) subgroups. Blood was collected via cardiac puncture under anesthesia for biochemical analysis, and pancreatic tissues were examined histopathologically and immunohistochemically. Both acute and subacute ZnO-NP exposure caused a significant rise in blood glucose and serum Zn. Insulin levels increased acutely but decreased with subacute exposure. The subacute group showed a significant increase in oxidative stress markers indicated by elevated malondialdehyde (MDA) compared to controls. Histological examination revealed pancreatic degeneration, whereas increased inducible nitric oxide synthase (iNOS) immunopositivity indicated an inflammatory response, suggesting the involvement of oxidative stress in both groups. Oral exposure to toxic doses of ZnO-NPs caused oxidative stress and structural damage in pancreatic cells, affecting insulin and glucose levels. These findings highlight the potential health risks of ZnO-NP exposure, particularly with prolonged use.