Impact of Embedded Military Metal Alloys on Skeletal Tissue

An established metal embedding technique will be used wtih Sprague-Dawley rats consisting of a low dose of each metal of interest (depleted uranium, tungsten/nickel/cobalt, tungsten/nickel/iron). A control group will be used consisting  of a biologically inert metal, tantalum. Nine days prior to euthanisia animals will be injected with alizarin red and two days prior to euthanasia animals will be injected with calcein. The use of two labels will provide clarity for microscopic evaluation of bone formation. Animals will be euthanized at timepoints of 30 and 90 days post implantation. Necropsy will be performed biological samples processes. Whole blood will be drawn and process for complete blood counts with differential. One femur will be flushed of marrow and cell counts performed. Serum will be used for osteocalcin and TRAP-5b ELISA. Distal tibia will be embedded in methylmethacrylate and cut  for both evaluation of stained sections as well as unstained fluoresence. One femur will be sent to the  Univerisity of Indiana for micro computed tomography  in order to evaluate bone density. 

Statistical analysis will be completed using SPSS statistical software. The analysis of the data will focus on  determining any changes in bone density as measured by micro CT, bone formation or bone loss as measured by osteocalcin, TRAP-5b, and histomorphometry. 

The established pattern of military metal alloy deposition into a living organism demonstrates that bone is a primary deposition site. Currently, very little is known regarding the impact that these highly specialized metals have on skeletal tissue. This study represents a starting point for establishing an increased risk of osteoporotic fractures in combat wounded veterans with embedded military metal alloys.

Final Report is available on NTRL: https://ntrl.ntis.gov/NTRL/dashboard/searchResults/titleDetail/PB2017102...