Histopathological effects in the palate of the rat induced by injection with different black‐pigmented Bacteroides strains

Abstract

The present investigation was carried out in order to study the histopathological effect and virulence of different black‐pigmented Bacteroides species on both soft and hard tissues in an animal model. Male Wistar rats were injected in the palate next to the first right molar with 30 μl of a bacterial suspension containing 5 × 1010 viable cells per ml. To determine the difference in virulence the histopathological effects were studied five days after injection. All strains tested caused a submucosal infiltrate at the injection site, consisting of mononuclear cells, mainly lymphocytes, monocytes and fibroblasts. These inflammatory responses were accompanied by devitalization and resorption of bone. Simultaneously active osteoblasts and bone formation were observed. Strains of Bacteroides asaccharolyticus, Bacteroides melaninogenicus, Bacteroides corporis, and Bacteroides loescheii caused a less prominent devitalization of the palatinal bone than strains of Bacteroides gingivalis and Bacteroides intermedius. Strains of the latter species caused often a nasal infiltrate and abundant bone formation at the nasal side of the palatinal bone. B. asaccharolyticus and B. melaninogenicus scarcely caused signs of a reaction at the nasal side of the palatinal bone. In a second longitudinal study the histopathological effects of B. gingivalis strain HG 66 were investigated. The inflammation was characterized by a rapid influx of polymorphonuclear cells within 2 to 4 hours. These cells gradually diminished and were replaced by a mononuclear infiltrate. One of the most characteristic features accompanying the inflammation was the disappearance of the periosteum. After two days a recovery of periosteum was observed and the osteoblasts became active in new bone formation. Devitalization from the palatinal bone started about 8 hours after injection and could be seen until 10 days after injection. No inflammatory reaction or devitalization of bone could be observed 15 days after injection.

Histopathological Changes in the Hind Foot of the Mouse Induced by Black-Pigmented Bacteroides Strains

“…However, demonstration of the potential of these bacteria to stimulate bone resorption would suggest involvement in periodontal disease but this has not been widely studied (Heijl et al, 1980;Roeterink et al, 1984). Studies on periodontal bone destruction in gnotobiotic and conventional animals have shown effects of several bacterial species (Page and Schroeder, 1982).…”

“…B. gingivalis and B. intermedius strains, which form a significant part of the cultivable microflora from periodontal diseased sites (Slots, 1982), proved to be more virulent in regard to bone resorption than some strains of the other species. In other animal models, these bacteria also cause different types of infection (van Steenbergen et al, 1982;Roeterink et al, 1984) but B. gingivalis seems to be the most virulent black-pigmented Bacteroides species.…”

Pathogenicity of Prevotella intermedia and Prevotella nigrescens isolates in a wound chamber model in rabbits

“…In anaerobic infections of other body sites, such as pleuropulmonary infections, gangrenous or perforated appendicitis and abscess formations in the head and neck region (12,40), P. intermedia seems to be a common participant. P. intermedia isolates have been shown in experimental models to be capable of producing pathologenic reactions (33,41).…”

“…This study addressed the question of whether P. intermedia and P. nigrescens subtypes would show a virulence difference in an experimental wound chamber model in rabbits. Porphyromonas gingivalis strains were incorporated in the study as a reference due to its documented pathogenicity (5,14,20,26,33).…”

Generation and degradation of the complement fragment C5a in human serum by Bacteroides gingivalis

“…Baeteroides gingivalis can cause rapidly spreading purulent infections when inoculated into guinea pigs and mice (9,17,20,28). This organism has also been implicated in the pathogenesis of periodontal disease (4,12,24).…”