Null effects of C5 inhibition on functional and tissue outcomes after traumatic brain injury in mice

The complement system plays a critical role in the pathophysiology of traumatic brain injury (TBI). This study examined the effects of complement component C5 inhibition on functional recovery, edema formation, and histopathological outcomes following moderate TBI. Male C57BL/6 mice received the monoclonal anti-C5 antibody BB5.1 or an isotype control antibody two hours before TBI induction as induced using controlled cortical impact (CCI), with a second dose given four days post-injury. Functional outcomes were assessed at 2 and 24 h, and on days 3, and 7 post-injury. Histopathological evaluations were carried out on day 1 and 7, and post-mortem magnetic resonance imaging was used on day 7 to quantify edema and lesion volumes. In summary, no significant differences in neurological deficits were observed in mice treated with BB5.1 in both the short-term and longer-term experiment. Furthermore, no difference in edema and lesion volume was observed in both the histopathological analyses and MRI data.