Mycoplasma Hyorhinis Swine Arthritis. II. Morphologic Features

Abstract

Mycoplasrna hyorhinis arthritis, induced in young Yorkshire swine, can be considered as a three-stage process. The first 3 weeks of the disease were characterized by a severe polyserositis and mild synovitis. In the second stage, mononuclear cell infiltration of the synovium and other tissues was apparent. In the final stage, beginning about 3 months after inoculation, lymphocytic aggregates had become nodular, synovial hypertrophy was pronounced, and bone and cartilage destruction by pannus was common. Continued activity was apparent to Day 224.The polyarthritis which develops after the intraperitoneal inoculation of Mycoplasma hyorhinis into young Yorkshire swine is described in the accompanying report (1). That pilot study was undertaken in order to evaluate more chronic disease than has been previously reported (2, 3) and to compare the observed findings to rheumatoid arthritis.The key features of such comparisons are the histopathologic changes, especially in the articular tissue, and the duration of active disease contrasting a potentially selflimiting mycoplasmal infection to the life- long nature of rheumatoid arthritis. This report details the evolution of the gross and histologic findings up to Day 224 of the experimental illness and points up certain features pertinent to its chronicity. MATERIALS AND METHODSThe animals studied, the experimental inocula used, and the circumstances of the study are described in the accompanying paper (1).At preselected intervals, or at times required by life threatening illness, control or infected animals were anesthetized with intravenous sodium pentobarbital and were sacrificed by carotid artery bleeding. In human anatomic terms, the shoulders, elbows, wrists, hips, knees and ankles were opened and examined grossly. Specimens for histology were taken from each of the 12 joints. Tissue was also obtained from a number of viscera and from the central nervous system. Specimens for histologic examinations were fixed in 10% buffered formalin and stained with hematoxylin and eosin. Selected tissues were also stained with toluidine blue, safranin 0-fast green, phosphotungstic acid-hematoxylin, Masson and Gram stain.In order to compare synovial specimens, a histologic grading scheme was devised. Seven major categories were evaluated: (a) presence of a fibrin and inflammatory cell exudate, primarily polymorpho- 202

Rheumatoid-Like Joint Lesions in Rabbits Injected Intravenously with Bovine Serum

“…The natural lodgement of micro-organ isms in the joints of animals, such as strep-tococci, staphylococci, pneumococci [Cec/7 el al., 1939], Mycoplasma [Barden and Decker, 1971;Ennis et al, 1971] and Erysipelothrix [Collins and Goldie, 1940] with the production of local inflammatory res ponses resembling rheumatoid lesions offers an attractive experimental approach and one which is important in our understanding of the aetiology of RA in man.…”

Mycoplasma hyorhinis Swine Arthritis III. Modified Disease in Piney Woods Swine

“…Randomly selected animals were killed during week 1 and at intervals thereafter up to week 49, the end of the study. The postmortem microbiological and histopathological sampling and assessment techniques have been described (2). Each joint was given a rating from 0 to 3 on each of seven pathologic criteria: fibrosis, perivascular cuffing, mononuclear infiltration, villous hypertrophy, lining cell hyperplasia, neovascularization, and surface fibrin.…”

Perturbations of gut microbiome and metabolome of pigs infected with Mycoplasma hyorhinis

“…1 Mycoplasma hyorhinis, which often colonizes the upper respiratory tract and tonsils of swine, is a bacterium within the class Mollicutes, which lacks cell walls. 2,3 Existing studies have reported that it is a common cause of pneumonia, polyarthritis, and arthritis, [4][5][6] and also can lead to growth retardation. 7 Moreover, M. hyorhinis usually coinfects with a variety of other pathogens in swine production.…”