Can zinc protect cells from the cytotoxic effects of cobalt ions and nanoparticles derived from metal-on-metal joint arthroplasties?

Objectives Recently, high failure rates of metal-on-metal (MOM) hip implants have raised concerns of cobalt toxicity. Adverse reactions occur to cobalt nanoparticles (CoNPs) and cobalt ions (Co2+) during wear of MOM hip implants, but the toxic mechanism is not clear. Methods To evaluate the protective effect of zinc ions (Zn2+), Balb/3T3 mouse fibroblast cells were pretreated with 50 mu M Zn2+ for four hours. The cells were then exposed to different concentrations of CoNPs and Co (2+) for four hours, 24 hours and 48 hours. The cell viabilities, reactive oxygen species (ROS) levels, and inflammatory cytokines were measured. Results CoNPs and Co2+ can induce the increase of ROS and inflammatory cytokines, such as tumour necrosis factor alpha (TNF-alpha), interleukin-1 beta) (IL-1 beta) and interleukin-6 (IL-6). However, Zn pretreatment can significantly prevent cytotoxicity induced by CoNPs and Co2+, decrease ROS production, and decrease levels of inflammatory cytokines in Balb/3T3 mouse fibroblast cells. Conclusion These results suggest that Zn pretreatment can provide protection against inflammation and cytotoxicity induced by CoNPs and Co2+ in Balb/3T3 cells.