Fig. 6

Complement receptor 2 protects against synapse loss following sciatic nerve transection. Expression of C1q is up regulated in mice following SNT, without discernible strain differences (a). C3 demonstrates a strong trend towards increased expression in the injured side ofthe cord in Cr2 ^−/− but not WT mice (p = 0.048, t test), but does not quite reach significance (b). Cr2 is significantly up regulated following injury in WT mice (c). Assessment of synaptic density by quantification of synaptophysin immunolabeling signal demonstrates increased loss in Cr2 ^−/−, suggesting that CR2 protects from synapse elimination following nerve injury (d–f). The white box shows a motor neuron on the control and injured sides, respectively, where the dense synaptic synaptophysin-labeled aura surrounding the cell body is lost on the axotomized cell (e and f). IL ipsilateral, CL contralateral. Scale bar equals 40 μm. n = 6 + 5 RT-PCR, 8 + 8 IHC; *p < 0.05, **p < 0.01, and ***p < 0.001. The results are represented as mean ± SEM