Structural changes in femoral bone tissue of rats after intraperitoneal administration of nickel

The present study investigated the acute effects of nickel (Ni) on macroscopic and microscopic structure of femoral bone tissue in rats. For this purpose, ten 5-month-old male Wistar rats were injected intraperitoneally with a single dose of 15 mg NiCl2 per kg of body weight. Ten 5-month-old males without Ni supplementation served as a control group. Forty-eight hours after Ni administration, all animals were killed, and their femora were collected for macroscopic and microscopic evaluation. We found that intraperitoneal application of Ni had no significant effect on femoral weight and femoral length in rats. On the other hand, cortical bone thickness was significantly higher in rats administered Ni (P<0.05). Also, a decreased number of primary and secondary osteons was observed in the microstructure of these rats’ bones. Morphometrical measurements showed a significant increase in all variables (area, perimeter, maximum, and minimum diameter) of the primary osteons’ vascular canals, Haversian canals, and secondary osteons (P<0.05) in rats from the experimental group. Our results suggest that intraperitoneal injection of NiCl2 at the level used in this study had no impact on the macroscopic structure of femora of adult male rats; however, it significantly influenced the microscopic structure of their compact bone.