Fig. 11.
Dog hematoxylin and eosin (H&E)/collagen/mast cells. Histology from the lumbar spinal cord of a dog that received infusions of morphine (25 mg/ml/0.5 ml/day) for 28 days. (A) Low-power view of the catheter site (*) and pericatheter inflammatory reaction stained with H&E. This animal has a severe inflammatory reaction, with infiltrate throughout much of the subarachnoid space and extending through the dura into the epidural space. The areas designated (b), (c), and (d) are shown at higher magnification in (B), (C), and (D). Scale bar = 300 μm. (B) The inflammatory reaction close to the catheter consists of abundant polymorphonuclear cells (pmn), plasma cells (pl), and some lymphocytes and macrophages (not marked in this image), intermixed with fibroblasts (fib). Reactive endothelial cells (en) suggest neovascularization. Scale bar = 50 μm. (C) Further away from the catheter, there are fewer polymorphonuclear cells, but still abundant plasma cells (pl) and some lymphocytes (L) intermixed with fibroblasts (fib). Scale bar = 50 μm. (D) The inflammatory reaction extends to and the cell in this location consists predominantly of fibroblasts (fib) and macrophages (mac). Scale bar = 50 μm. (E) Herovici collagen stain. Medium power view of the pericatheter reaction in a location similar to that labeled (d) in image (A). The catheter site (*) is on the left, dura on the right. Dense bands of mature collagen (redstain, examples at red arrows) are seen in the dura. The collagen bands in the dura are separated by inflammatory infiltrate. The inflammatory reaction on the left (gran) is within the arachnoid/subarachnoid space. The area designated (f) is shown at higher power in (F). Scale bar = 200 μm. (F) The region of the inflammatory reaction furthest from the catheter has more mature collagen (redstain, examples at red arrows) than the region closer to the catheter (bluestain, examples at blue arrows). Scale bar = 50 μm.