Figure 4

Attenuated intracerebral complement C3 levels in head-injured Cr2 ^-/- mice at 24 hours post injury. Panel A shows a representative western blot of brain homogenates from injured (left) and uninjured (right) hemispheres of wild-type and Cr2 ^-/- mice at 24 hours after head injury or sham surgery, using a monoclonal anti-mouse C3 antibody. Equal protein loading (50 μg per lane) was ensured by control blotting with β-actin. Closed head injury induced an increase of C3 protein levels in the injured hemispheres of wild-type mice compared to sham controls. In contrast, head-injured Cr2 ^-/- mice showed attenuated intracerebral C3 levels in the injured left hemisphere. Pixel intensity for densitometric quantification was determined using ImageJ software. The western blot shown in the figure is representative of four individual experiments. Panel B demonstrates the extent of C3 brain tissue deposition by immunohistochemistry using monoclonal anti-mouse C3 as primary antibody. Similarly as shown by the western blot data, C3 tissue deposition was attenuated in head-injured Cr2 ^-/- mice, compared to wild-type littermates. The inserts in the upper panel (40 ×) reflect the according selection in the corresponding higher magnification images (100 ×). TBI, traumatic brain injury.