Evaluation of the toxic effect of silver nanoparticles and the possible protective effect of ascorbic acid on the parotid glands of albino rats: An in vivo study

This study aimed to evaluate the toxic effect of silver nanoparticles (AgNPs) on the parotid glands (PGs) of albino rats histologically and ultrastructurally and assess the possible protective effect of ascorbic acid as an antioxidant. Thirty male albino rats weighing between 150 mg and 200 mg were divided into three groups: the control group (C1) contained 10 rats that received 2 mg/kg (body weight (bw)) of aqueous nitrate buffer by intraperitoneal (IP) injection daily for 28 days; the AgNPs group contained 10 rats that received 2 mg/kg (bw) IP AgNPs daily for 28 days; and the AgNPs-vitamin C group contained 10 albino rats that received 2 mg/kg (bw) AgNPs IP daily for 28 days with oral administration of 100 mg/kg (bw) vitamin C in drinking water daily for 28 days. The PG acinar and ductal cells of the AgNPs group showed signs of toxicity and degeneration characterized as pleomorphic nuclei, binucleation, cytoplasmic vacuolations, and stagnated secretion in the ductal lumen. In addition to degenerated mitochondria, dilated rough endoplasmic reticulum and lysosomes were filled with AgNPs (p < 0.001). The AgNPs-vitamin C group showed significantly less degenerative changes histologically and ultrastructurally compared to the AgNPs group (p = 0.002). AgNPs produced significant toxic effects on the PG of albino rats, presumably through the generation of reactive oxygen species and toxic ion release, and administration of vitamin C was shown effective in decreasing these toxic effects.