Experimental arteritis in young rats induced by Erysipelothrix rhusiopathiae

Area of Science:

• Veterinary Pathology
• Microbiology
• Immunology

Background:

• Arteritis, or inflammation of arteries, can have various causes.
• Erysipelothrix rhusiopathiae (E. rhusiopathiae) is a bacterium known to cause disease in animals.

Purpose of the Study:

• To investigate the acute phase of arteritis induced by viable Erysipelothrix rhusiopathiae in young rats.
• To elucidate the role of bacterial neuraminidase in the pathogenesis of E. rhusiopathiae-induced arteritis.

Main Methods:

• Induction of arteritis in rats via inoculation with viable E. rhusiopathiae.
• Histopathological examination of arterial tissues to assess cell infiltration and degeneration.
• Immunofluorescence techniques to detect bacterial invasion, desialylation, and complement component C3 deposition.

Main Results:

• Cell infiltration was observed in the periarterial tissue and outer media within three days post-inoculation, preceding bacterial invasion.
• E. rhusiopathiae invaded the adventitia and outer media, but not the inner media or intima.
• Neuraminidase activity, indicated by desialylation, was detected in areas of bacterial invasion, and C3 was found along the adventitia.
• Arteritis was induced specifically by viable bacteria, not heat-killed bacteria or culture supernatant.
• The induced arteritis predominantly affected large or medium-sized muscular arteries.

Conclusions:

• Viable Erysipelothrix rhusiopathiae can induce arteritis in muscular arteries.
• Bacterial neuraminidase produced by E. rhusiopathiae likely plays a role in the pathogenesis of this arteritis.