01899nas a2200289   4500000000100000008004100001260001300042653001200055653002100067653001200088653001600100653002500116653001200141653002500153653000900178653002100187653001500208100001500223700001500238700001900253245013400272856004100406300001000447490000700457520113100464022001401595       1979                            d  c1979 Dec10aAnimals10aAnimals, Newborn10aleprosy10aMacrophages10aMicroscopy, Electron10aMuscles10aMycobacterium leprae10aRats10aRats, Inbred Lew10aThymectomy1 aDawson P J1 aRingus J C1 aFieldsteel A H00aNeonatally thymectomized Lewis rats infected with Mycobacterium leprae. 2. Histopathologic and electron microscopic observations.  uhttp://ila.ilsl.br/pdfs/v47n4a01.pdf  a561-90 v473 a<p>We report the histologic and electron microscopic findings following intravenous inoculation of M. leprae into neonatally thymectomized Lewis rats, which were killed one to two years later. All organs appeared normal grossly. Histologic changes were confined to the footpads, snout, ears, tail, and testes, all of which were involved in every rat. The tissues were edematous and infiltrated by varying numbers of foamy macrophages. In the footpads muscle fibers were vacuolated, and small nerves showed degenerative changes. Large numbers of M. leprae were present in macrophages and striated muscle cells and smaller numbers in perineural cells and pericytes, as well as lying free in the tissues. Occasional intracellular bacilli were found throughout the reticuloendothelial system. Electron microscopy confirmed that the majority of organisms were within activated macrophages. Both intact and fragmented bacilli were contained within double-membrane bound vacuoles. Numerous M. leprae were lying free within the sarcoplasm of striated muscle cells. Virtually all of the extracellular organisms were degenerating.</p>
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