Evaluation of oxidative stress after fractures. A preliminary study

In a preliminary attempt to see if oxidative stress occurs after major fractures, we evaluated two groups of patients sustaining a single fracture (Group A) and multiple fractures (Group B), and compared them with healthy controls (Group C). Indirect evaluation using plasma was done, as serial samples directly from bone could not be taken in humans. We measured plasma levels of malonyldialdehyde (MDA), which depicts the lipid peroxide content, and the unstable nitric Acid (indirectly through measuring reactive nitrogen intermediates and citrulline), serially over a four-week period. The endogenous ferric reducing anti-oxidant power assay (FRAP) was also done. All these have been proven to be representative of oxidative stress in other situations. We noted significant changes in these values, peaking by the 2nd and 3rd weeks post fracture, and coming down by the 4th week. This implies that oxidative stress does occur after a fracture; the initial few days are eventless, probably because the fracture causes a local region of ischaemia. Oxidant levels rise by the 2nd and 3rd week, perhaps due to callus formation and angiogenesis, which results in reperfusion at the fracture site. Oxidative stress may also be proportional to the number of bones fractured, as Group B, with multiple fractures had more elevated values. The antioxidant levels also behave similarly to combat the detrimental effect. The pro and antioxidants values then gradually decline by the 4th week, probably because by then the bone starts to organize. A better understanding of these mechanisms may help in defining the role of oxidative stresses after fracture and perhaps better define the role of antioxidants in helping fracture healing.