Photoperiod affects hepatic and renal cadmium accumulation, metallothionein induction, and cadmium toxicity in the wild bank vole (Clethrionomys glareolus)

The objective of this study was to examine the toxic effects of dietary cadmium (Cd) on bank voles, being the F1 offspring of a wild-caught population. For 6 weeks, the rodents were provided with diets containing 0.05 (control), 40, 80, and 120 μg Cd/g dry wt of diet under moderate (12 h) and long (16 h) photoperiods. Histological examinations and analyses of metallothionein (MT), Cd, Cd bound and not bound to MT, iron and lipid peroxidation in the liver and kidneys were carried out. Histopathological changes occurred in the liver (infiltrations of leukocytes) and kidneys (hemorrhage, glomerular injury, tubular cell degeneration) of bank voles fed the highest dose of dietary Cd only under the moderate photoperiod. The same voles also exhibited the highest values of hepatic and renal Cd, Cd not bound to MT, and renal lipid peroxidation. It seems that under the long photoperiod the liver and kidneys of bank voles were protected against Cd-induced injury through decreasing Cd accumulation and increasing synthesis of MT.