Evaluation of local and systemic effects after intramuscular implatation of lead shot alternatives in rats

Abstract

Objective - To evaluate the local and systemic effects of IM implantation of lead shot alternatives in rats. Animals - 22 laboratory rats. Procedures - Sterile IM implantation of shot metals was performed, with euthanasia and necropsy at 2, 8, 16, and 26 weeks after implantation. Skeletal muscle specimens were examined histologically and kidney specimens were tested for heavy metals. In vivo and in vitro evaluation of corrosion of metals was performed. Results - Corrosion of susceptible metals was greatest at 2 weeks in vivo and in vitro. Inflammation associated with all pellet types was greatest 2 weeks after implantation. Nickel-plated steel incited significantly greater inflammation at 2 weeks, compared with bismuth alloy. Kidney iron concentration was significantly greater at 26 weeks, compared with other test periods. Local tissue deposition of iron was verified by use of Prussian blue staining for all iron-containing metals. Concentration of arsenic in kidneys was significantly greater at 8, 16, and 26 weeks after implantation, compared with 2 weeks. Clinical relevance and impact for human medicine - Humans or dogs wounded with nickel-plated steel may require more aggressive initial monitoring than those wounded with other shot types. Monitoring of systemic arsenic concentrations may be indicated in patients wounded with shotgun pellets.