Scanning electron microscopy of the subarachnoid macrophages after subarachnoid haemorrhage, and their possible role in the formation of subarachnoid fibrosis.

Sixty dogs with experimental subarachnoid haemorrhage (SAH), repeated SAH, and subarachnoid fibrosis (examined three weeks and three months after SAH, and treated with urokinase or dexamethasone) were examined by scanning electron microscope (SEM). The authors observed the resting and activated macrophages, the erythrophagocytosis, and giant cells in the subarachnoid space after SAH. They consider that the macrophages play an important role in the formation of subarachnoid fibrosis, similar to the role of macrophages in fibrosis in other sites.