Fig. 4

Physical characterization and morphometry of tibial nerves in armadillos. Armadillos were infected with M. leprae then had their posterior tibial nerves biopsied 28 months later. In a electron micrographs of a tibial nerve were taken. In (i), both Remak bundles (arrows) and myelinated axon are observed in nerves collected from an uninfected animal, with a Remak axon containing a cluster of mitochondria indicated (Ax). In (ii), a myelinated axon from a M. leprae-infected armadillo (broken arrow) with a M. leprae bacillus (white arrow) bounded by vacuolated axoplasm is shown. In (iii), a microphotograph of a M. leprae-infected tibial nerve section containing Remak bundles (solid black arrows) and a myelinated axon (broken black arrow) can be seen, along with M. leprae in axoplasm and Schwann cell cytoplasm (white arrows) exhibiting edema and degeneration (arrow head). In (iv) a Remak Schwann cell (black arrow) with M. leprae (white arrow) undergoing degeneration is identified. In (v), nerves from a LepVax-immunized armadillo showed an occasional intraneural macrophage (arrow head) adjacent to Remak axons (arrow), and in (vi) a Remak bundle (arrow) without any degenerating changes. Scale bar, 1 µm. in b, axons within Remak bundles in tibial nerves were enumerated. In c, axon diameters were measured. Results are shown as mean and s.e.m, with a minimum of 810 measurements made for each group. In d, Schwann cell diameters were measured. Results are shown as mean and s.e.m, with a minimum of 550 measurements made for each group. ***p-value < 0.0001