Effects of Nickel by Gavage and Intraperitoneal Injection on Histomorphology, Nutrient Metabolism, Major and Trace Elements in Mice.

Nickel (Ni), an essential trace element, poses growing environmental and health risks due to industrial activities. This study evaluated nickel toxicity in mice via gavage and intraperitoneal injection, analyzing(i) histopathological damage, (ii) macronutrient metabolism, assessed by crude protein (CP) and crude fat (CF) contents and (iii) the tissue distribution of trace and major elements. Histopathological injuries were assessed via H&E staining, while CP and CF levels were quantified using the Kjeldahl method and Soxhlet extractor method. Flame atomic absorption spectrometry measured Ni, Calcium (Ca), Manganese (Mn), Magnesium (Mg), Copper (Cu), Zinc (Zn), and Ferrum (Fe) concentrations. Both administration routes induced dose-dependent damage to the duodenum, jejunum, ileum, liver, lungs, and kidneys. Gavage primarily injured the small intestine and liver, whereas intraperitoneal injection predominantly affected the liver and kidneys. Intestinal villus/crypt values (V/C), CP, and CF decreased significantly with rising nickel doses (P<0.05). Tissue nickel accumulation increased proportionally with exposure levels, accompanied by reduced Fe and Cu concentrations and elevated Zn in specific organs. Ca, Mn, and Mg levels remained stable across treatments.