Cadmium-induced pancreatic toxicity in rats: comparing vitamin C and <i>Nigella sativa</i> as protective agents: a histomorphometric and ultrastructural study

The study aimed to assess the toxic effect of cadmium (Cd) on the exocrine and endocrine functions of pancreas, the changes in pancreatic tissue after Cd withdrawal, and the protective effects of vitamin C (VC) and <i>Nigella sativa</i> (<i>NS</i>) against Cd-induced damage. Rats were assigned to: control, Cd-treated (0.5<b> </b>mg/kg/d intraperitoneal [IP] injection), VC and Cd-treated (receiving 100 mg/kg/d VC orally and Cd concomitantly), <i>NS</i> and Cd-treated (receiving 20 mg/kg/d <i>NS</i> and Cd, simultaneously), and Cd withdrawal (receiving Cd for 30 d then living free for recovery for other 30 d). Blood samples were collected and post-sacrifice pancreatic specimens were processed for light and electron microscope study. Quantitative analyses of pancreatic collagen area%, pancreatic islet parameters, β cell density, and insulin immunoexpression were done. Fasting blood glucose was significantly increased in Cd-treated and Cd-withdrawal groups, while co-treatment with VC and <i>NS</i> caused significant reductions (<i>p</i> < 0.05). Cd-induced extensive degenerative changes in pancreatic acini and islets at light and ultrastructure levels. Obvious fibrosis and congestion of blood vessels were noticed. Significant reductions in pancreatic islet number, volume, and surface area and diminished beta cell count and insulin immunoexpression were observed. After withdrawal of Cd, the whole pancreatic tissue still showed a serious impact. Concomitant treatment with VC or <i>NS</i> obviously reduced these degenerative changes and significantly improved pancreatic islet parameters and insulin immunoexpression. VC showed a better amendment than <i>NS</i>, but this difference was statistically insignificant. Therefore, VC and <i>NS</i> could be used as prophylactic agents that lessen Cd consequences on the pancreas.