Bone Abstracts

Cadmium (Cd) is regarded as a risk factor for various bone diseases in humans and experimental animals. To compare effects of different routes of Cd administration on femoral bone structure, ten 4-month-old male Wistar rats (group A) were injected intraperitoneally with a single dose of 2 mg CdCl₂/kg body weight and killed 36 h after Cd had been injected. Ten 1-month-old male rats (group B) were dosed with a daily Cd intake of 30 mg CdCl₂/l in drinking water for 90 days and then were killed. Both groups were compared to the control group (C) of 10 males without Cd intoxication. Macroscopic structure of femur and detailed histological analyses of compact bone tissue were performed in each group. Our results revealed the significant effect of peroral exposure to Cd on femoral weight and qualitative histological characteristics of the bone in rats from the group B. In these rats, bone microstructure was different in the middle part of substantia compacta where primary vascular radial tissue occured. Also, some resorption lacunae indicating osteoporotic changes near endosteal surface were observed. The different route of Cd administration induced an opposite effect on the size of the primary osteons’ vascular canals and Haversian canals in groups A and B. Values of all variables (area, perimeter, maximum and minimum diameter) of these structures were significantly increased (P<0.05) in rats from the group A. In contrast, they were significantly decreased (P<0.05) in the group B rats. The size of secondary osteons was not affected by the route of Cd exposure, it was significantly lower (P<0.05) in both groups (A and B). Results of this study suggest route- and time-dependent effects of Cd on femoral bone structure in adult male rats. This study was supported by the grants KEGA 025UKF-4/2012; 035UKF-4/2013.